Weyl and
Emmy -- Posted by wostraub on Wednesday, December 21 2005
Here's a photo taken in
the early 1930s of Weyl and his wife Hella, their son Joachim, Emmy Noether
and several friends, colleagues and students. Reproduced from the 1981 book
Emmy Noether: A Tribute to Her Life and Work, James Brewer and
Martha Smith (eds.).
Weyl Left -- Posted by wostraub on Tuesday, December 20 2005
Hermann Weyl was a patriotic
German citizen, but when Hitler came to power in 1933 Weyl saw the writing
on the wall. As a respected mathematical physicist and law-abiding
Christian, he had nothing to fear himself, but his wife Helene had a Jewish
background which placed her in jeopardy. They gave up their bank accounts
and all their possessions, packed their bags, and left for Princeton.
Albert Einstein and Emmy Noether weren't far behind them.
Now that Bush is turning America into Nazified Amerika, where would Weyl
go? My guess is back to Germany or Switzerland. He wouldn't have anything
to do with this Bush regime.
It's still not so bad, they say. You can still speak out against the Bush
regime without worrying about being taken away in the middle of the night.
Or can you? According to Bush, you're either with him or you're with the
terrorists. The Democratic and Independent parties are not with Bush, so
they must be for the terrorists. Bush's latest crime is to spy on Americans
without a court order. My guess is that he will now authorize his goons at
the NSA to spy on these parties to keep them from gaining power in 2006 and
2008. The Republican Party, in the guise of a Frist or Hastert or DeLay or
Sessions or Hunter or Inhofe, will then become Dictator for Life. George Orwell
may have been off by only 24 years.
If Bush is successful, and I see no reason to believe that he won't be
unless he is stopped, then you can say goodbye to the America you once knew
and loved. Say goodbye also to the Constitution, which Bush recently
referred to as "just a goddamned piece of paper." Say goodbye
also to the middle class, which will be taxed out of existence to pay off
Bush's monstrous deficits. You can also kiss off human rights, the
environment and legitimate science, because these niceties have no place in
BushWorld.
As for me, I'm going to fight like hell in 2006 to keep these nightmares
from becoming reality, and I hope your New Year's resolutions are along the
same lines. If we fail, we won't recognize the place we're living in. God
help us all.
Guns,
Germs and Steel --
Posted by wostraub on Thursday,
December 15 2005
One day in 1972, the UCLA
evolutionary biologist Jared Diamond was walking along a beach in New
Guinea with a local politician named Yali. At one point, the native New
Guinean asked Diamond the question, "Many years ago, you white people
developed many advanced goods and brought them here. Why did we black
people develop so little of own own?"
The answer to that question became the subject of Diamond's 1997 book, Guns,
Germs and Steel. I have just finished reading this award-winning book
on human history and biology, and I am astonished by how much I have
learned about the human condition.
You might recall a book called The Bell Curve from about ten
years' back that basically posited the very contentious notion that whites
are more intelligent than blacks, and it is because of this that Europeans
ended up on top in the world-dominance game. But Diamond completely
destroys that idea by showing that it was a series of accidents --
biological, geographical and otherwise -- that is the real explanation for
why Africa and other dark-skinned nations were plundered by whites. It
could easily have been the other way round.
Diamond capably argues that whites, on the whole, are probably somewhat
less intelligent than blacks, but the difference is meaningless. What
really counted when the world was being "civilized" 500 hundred
years ago was the confluence of numerous accidents affecting human food
production, mobility, disease resistance/immunity, language development,
animal domestication, and availability of local resources.
For example, Europeans were able to domesticate most of their indigenous
animals for work and food. Pigs, sheep, cattle, oxen, chickens, ducks and
dogs were just some of the critters that were domesticable. By contrast,
sub-Saharan Africans had all assortment of local widlife that could not be
domesticated. As a case in point, Diamond describes efforts that were made
many years ago to domesticate the zebra to pull carts and plow fields.
These efforts were quickly abandoned because zebras simply cannot be
sufficiently tamed to serve as beasts of burden. It goes without saying
that no hippo, lion or hyena ever had to pull a wagon.
Neither is inhuman brutality solely attributable to whites. In societies
where one band of indigenous natives had an advantage over others, the advantaged
peoples happily attacked, slaughtered and enslaved their less-fortunate
neighbors, regardless of the color of their skin. In other words, Diamond
explains, if things had been different, black civilizations ably probwould
not have restrained themselves from brutally exploiting their less-powerful
white brothers.
However enlightening the book was for me, it does not adequately take into
account the apparent lack of compassion that humans are capable of, if not
altogether inclined to. And while the last chapter of Diamond's book is
titled The Future of Human History as a Science, it does not touch
on the need for humans to act cooperatively and humanely in an age of
diminishing resources and greatly expanding human populations.
To me, reading about human history and all its compound tragedies makes the
words, teachings and acts of Jesus Christ all the more remarkable. Christ's
love, wisdom, compassion and humility represent the most revolutionary kind
of humanity I can imagine. It's miraculous that anyone, god or mortal,
could have so understood the human condition.
Today, we live in an age of war, torture, deceit, secrecy and disregard for
our fellow human beings, perhaps more so now than ever before. Worse, my
own country has adopted these evils and somehow found a way to justify
them. It astounds me that we can attend church, pray and worship to the God
whose teachings constantly tell us that we are doing great wrongs. Yet this
is the way of hypocrisy, a unique human failing that itself is as old as
history.
The Spin
Connection in Weyl Space, Again -- Posted by wostraub
on Saturday, December 10 2005
I've completely rewritten
my article on Weyl and the spin connection from the point of view of
non-metric-compatible geometry. In this article, I express my doubts not
only about the validity of Weyl's original theory but that of
non-metric-compatible theories as well. Connection.pdf
Connections
in a Weyl Space --
Posted by wostraub on Friday,
December 2 2005
While updating my
previous write-up on Weyl's spin connection, I started looking seriously at
the concept of a generalized Weyl space and its relationship to variable
vector magnitude under parallel transfer. It does not look encouraging, and
I'm beginning to suspect that vector magnitude is a fixed quantity after
all.
In his 1918 theory, Weyl argued that vector length under physical
transplantation varies in an electromagnetic field. If the length of some
arbitrary vector Vμ is given by L2
= gμνVμVν, then
Weyl's theory basically says that under parallel transport this goes over
to 2LdL = gμν αVμVνdxα
or dL = AμdxμL, where gμν
α is the covariant derivative of the metric tensor and Aμ
is the electromagnetic 4-potential. However, I have not been able to find a
symmetric connection term Γαμν
(Weyl or otherwise) that allows for a non-zero dL and a vanishing
Kronecker delta tensor under covariant differentiation. It goes without
saying that dL = 0 kills Weyl's theory before it even gets
started.
This is not deep stuff, and I'm surprised that I've seen no real attempt in
the literature to address what appears to be an obvious discrepancy of Weyl
space. At the same time, I've read Weyl for years and never given this
issue a second thought!
Of course, everyone knows that Weyl's 1918 was wrong anyway, but the
argument that killed it (due to Einstein) was based on physical, not
mathematical, considerations. Einstein himself got wrapped up years later
in the same old game when he tried to find a non-symmetric
connection for parallel transport in spacetime. Indeed, the last sheet of
paper he ever wrote on (while in the hospital where he died) is covered
with non-symmetric connections, which were integral to his final (and
failed) unified field theory. I like to think that when Einstein stood
before God, the Almighty asked him "With the mind I gave you, why on
Earth did you waste the last 30 years of your life on this nonsense?!"
A colossal waste of time, but fun stuff.
"The use of
general connections means asking for trouble." -- Abraham Pais, Subtle
is the Lord
PS: Very big game tomorrow for my old school, USC. I love my kids (UCLA grads), but -- Go Trojans!!
Lev Landau -- Posted by wostraub on Thursday, December 1 2005
"I sing of Olaf glad
and big ..."
Lev Landau was perhaps Russia's greatest physicist, and certainly one of
the world's leading scientists in the fields of atomic and nuclear physics,
astrophysics, low-temperature physics, thermodynamics, quantum
electrodynamics, kinetic theory, quantum field theory, and plasma physics
[whew]. His work on superfluid helium garnered Landau the Nobel Prize in
Physics in 1962.
Landau was born in Russia in 1908. After earning his undergraduate degree
at the age of 19 at LSU (that's Leningrad State University to you Louisiana
Tigers fans), he went on to get a PhD in physics in 1934 at Kharkov Gorky
State University, where he was appointed head of the department the
following year.
Landau was not only a brilliant scientist, he was an idealist whose
negative statements against Stalin earned him a trip to a Russian prison in
1938. The conditions there were so harsh (see photo taken during his
imprisonment) that Landau did not expect to survive even one year. But
repeated, impassioned (and politically motivated) pleas from Niels Bohr and
fellow Russian Petr Kapitsa to Stalin (who wanted Landau shot) caused the
Russian leader to back down, and he grudgingly ordered Landau to be
released in 1939.
After receiving the Nobel Prize in 1962, Landau was involved in a car accident
that left him with a fractured skull and eleven broken bones. The accident
destroyed his great mind, and he subsequently passed away from the
accident's complications in 1968.
Why bring up the subject of Landau? Because he had the courage to openly
criticize a national leader who ordered the deaths of as many as 20 million
Russians over his total reign. Under Stalin's despotic rule, Landau must
have known he was sticking his neck out. But he spoke out anyway.
Today, US President George W. Bush has legalized torture, killed tens of
thousands of innocent civilians, turned the media into an
entertainment/propaganda machine, lied to the American people and the world
for corporate profit and political power, and taken from the poor and given
it to the wealthy, not to mention being the source of a host of other
uncountable scandals, misrepresentations and falsehoods. The worst part is
that he commits these crimes while hiding behind our Lord and Savior Jesus
Christ!
Where are the outraged scientists today? Where are the scientific heroes
that are willing to temporarily set aside their thoughts on superstrings
and brane theory (not to mention advanced weapons design) and speak out
against the untruths we're subjected to daily, ranging from a criminal war in
Iraq to the outrageous stupidity being forced into the craniums of students
regarding intelligent design and other anti-science dogma?
Stalin was a lot more intelligent than Bush, but Bush is far more dangerous
because he's in charge of 10,000 nuclear weapons. Bush's hatred of
intellectual thought and rationality has made him the darling of an
increasing number of brain-dead Americans who cannot think for themselves
anymore. I have the same respect for President Bush as I would have for a
chimpanzee with a machine gun.
"I will not kiss your f***ing flag ..." ee cummings
Newton
Routs Einstein --
Posted by wostraub on Friday, November
25 2005
Yesterday, the Royal
Society announced the results of a "popularity contest" between
Sir Isaac Newton and Albert Einstein. When asked which scientist made the
most contributions to science, 86.2% of the Royal Society's voting scientists
opted for Newton. When the same question was posed to the general public,
Newton again beat out Einstein, with 61.8% voting for Newton.
Intestingly, when asked which scientist made the most contributions to
humanity, only 60.9% of the 345 Royal Society voting scientists voted for
Newton, while the public vote was virtually tied.
Newton was elected to the Royal Society in 1672, whereas Einstein came in
as a foreign member in 1921.
Although this is the 100th anniversary of Einstein's annus mirabilis,
or miracle year of 1905 (he wrote five fundamental papers that year,
including the ones on special relativity and the photoelectric effect),
Newton's achievements were deemed more remarkable overall.
Black Hole
in the Milky Way --
Posted by wostraub on Thursday,
November 3 2005
Chinese researchers using a bank of ten radio telescopes spread across the
United States have found further evidence that a supermassive black hole
inhabits the center of our galaxy, in the constellation Sagittarius.
Most scientists now believe that galactic cores host such objects, whose
sizes may range from hundreds of thousands to many millions of solar
masses.
The object at the center of our Milky Way Galaxy was estimated to be about
4 million times the mass of the sun. Using the formula for the radius of a
black hole, R = 2GM/c^2, the black hole's event horizon would fit
neatly between the earth and the sun.
This is great stuff, but in order to get the general public excited about
it, newspapers and magazines have to write stupid things like "black
holes are cosmic vacuum cleaners that gobble up stars and everything else
in their vicinity." But black holes do not suck! They are collapsed
stars whose gravity is so great that the star literally shrinks down to
ZERO VOLUME and INFINITE DENSITY. Outside the black hole, however, these
point-like objects behave like ordinary stars, except they don't shine
because they're essentially dead stars (and any light couldn't escape their
gravity, anyway). In fact, if our sun were to suddenly become a black hole,
the earth and other planets would continue in their orbits as usual,
although the sky would be darker than we've ever seen it.
Also, these articles never talk about the true nature of a black hole,
which is one of the most bizarre physical objects of God's creation the
human mind has ever encountered. The mathematics that describes them,
Einstein's theory of general relativity, is of course rarely mentioned to
the public.
Event horizons, ergospheres, Hawking radiation, time travel? No -- give us
talk about cosmic vacuum cleaners!
Theory of
Matter in a Weyl Manifold -- Posted by wostraub
on Sunday, October 30 2005
While cleaning out some
boxes today, I came across a reprint of a paper I received years ago
entitled Theory of Matter in Weyl Spacetime by David Hochberg and
Gunter Plunien of Vanderbilt University [Phys. Rev. D 43 3358
(1991)]. It's neat to see Weyl's original spacetime gauge theory pop up
from time to time in research papers, and this is one of the better ones.
The authors demonstrate how a Lagrangian that is linear (not quadratic) in
Weyl's version of the Ricci scalar R can be coupled with a scalar
field $\phi(x)$ to derive Einstein's gravitational field equations. But the
authors then go on to develop a Lagrangian in spinor form that couples the
Weyl gauge vector to fixed-chirality spinors that are identified with
neutrinos. I think Weyl would have found that really interesting, since his
massless form of the Dirac equation anticipated the existence and eventual
discovery of these guys!
Hochberg and Plunien conclude from their investigation that spacetime is
actually Weylian (and only approximately Riemannian) and that the Weyl
field is a form of dark matter. Neat stuff!
I have the article in pdf format and will post the thing if I can get
permission from the American Physical Society. It's a relatively easy paper
to follow and I think the effort is worth it (and it might just take your
mind off the Bush cabal for a while).
Atiyah on
Weyl -- Posted by wostraub on Monday, October 24 2005
In 2002 the noted
mathematician Sir Michael Atiyah wrote a biographical sketch of Hermann
Weyl that included reflections on Weyl's interests in philosophy and
writing. Here is the article in pdf format:
Weyl
Relativity -- Posted
by wostraub on Monday, October 10
2005
This morning I was
contacted by the great-granddaughter of Hermann Weyl, Elizabeth T. Weyl of
Mount Holyoke College in Massachusetts. She informed me that she is aware
of only several direct descendants of the great mathematician now living in
this country. Why so few?
Weyl was married twice. His first wife, Helene (nickname Hella) Joseph, was
a philosophy student at the University of Gottingen in Germany under Edmund
Husserl, who held the philosophy chair at the school. Weyl's early love of
philosophy appears to have sprung at least in part because of the influence
of his wife, whom he married in 1913. Weyl and Helene subsequently had two
sons, but I have not been able to learn anything about their lives.
(Elizabeth Weyl wrote that she is the daughter of the son of one of Weyl's
and Helene's two boys.)
Helene passed away in 1948, and in 1950 Weyl remarried, this time to Ellen
Lohnstein (or Lowenstein) Bar of Zurich (she was a sculptor). At the time,
Weyl was 64 and not yet retired from his position at the Institute for
Advanced Study in Princeton, New Jersey. He did retire in 1952, and the
couple traveled between Zurich and Princeton until Weyl's untimely death in
1955 while in Zurich. Even at the age of seventy, God took him too soon!
I think I mentioned some time ago that during Weyl's days at the ETH in Zurich (where he held the chair in
mathematics), the German-born Weyl was drafted by Germany to serve in the
First World War. Fortunately, the Swiss government secured an exemption for
Weyl, and he was allowed to stay in Zurich to continue his research. Also
during these days, Weyl and the 1933 Nobel Laureate Erwin Schrodinger
became best friends. I've read unsubstantiated (but probably true) claims
that Weyl was the source of mathematical inspiration for Schrodinger's wave
equation. Unlike many scientists, Schrodinger was a good-looking,
well-dressed bon vivant and a Don Juan of sorts, and I've even
seen some reports that Weyl's first wife, Helene, fell under his spell,
while, at the same time, Schrodinger's (probably long-suffering) wife Anny
was enamoured of Weyl!
Weyl and
Antimatter -- Posted
by wostraub on Tuesday, October 4
2005
In his famous paper Eleckron
und Gravitation (Zeit.f. Physik 56), Weyl wrote
It is reasonable to expect that in the
two-component pairs of the Dirac field, one pair should correspond to the
electron and the other to the proton. Furthermore, there should appear two
electrical conservation laws, which (after quantization) should state the
separate conservation of the number of electrons and protons. These would
have to correspond to a two-fold gauge invariance involving two arbitrary
functions.
I find it remarkable that
only one year after the appearance of Dirac's relativistic electron theory,
Weyl had the temerity to infer that the four-component Dirac spinor
referred to the electron and the only other positively-charged particle
then known, the proton. Of course, Dirac had also considered this
possibility, but I am not aware of any rash statements he made to that
effect so early in the game. Neither scientist at that time knew the
correct explanation intimately involved the existence of the
positively-charged antielectron or positron, the first antimatter
particle to be discovered (which was found by Anderson in 1932).
Nevertheless, Weyl's gutsy if incorrect 1929 prediction shows how bold an
erstwhile pure mathematician could be in a field not originally
his own. Courageous, too, because Weyl's equally-erroneous 1918 metric
gauge theory had seemingly predisposed him to mockery when he resurrected
the idea (although as quantum phase invariance) in his 1929 paper.
Birthday
Quiz -- Posted by wostraub on Thursday, September 29 2005
Here's a photo of
Einstein and some friends taken at the Institute for Advanced Study at
Princeton on the occasion of Einstein's 70th birthday (March 14, 1949).
Weyl is the gentleman in the back, third from the left. Can you identify
the others? The answer is below.
Yes, it's the film director Visconti, 5 points. Oops, that's from an old
Monty Python routine. From the left, they are: H.P. Robertson, Eugene
Wigner, Hermann Weyl, Kurt Gödel, Isador Rabi, Einstein, R. Ladenburg, J.R.
Oppenheimer, and G.M. Clemence.
Note how these gentlemen range in appearance from dapper to advanced geek.
Particularly geeky is the mathematician Gödel (pronounced girdle),
whose famous 1931 incompleteness theorems proved that in principle
not all math problems are solvable. Einstein looks not only nerdy here but
ancient as well; maybe it's just his hair. He got the Nobel Prize in
Physics in 1921. Rabi won the prize in 1944, I believe, while Wigner got it
in 1963. Some pretty smart folks.
30K for
Katrina Relief --
Posted by wostraub on Wednesday,
September 28 2005
My son Kristofer's
Internet site BlankLabel
raised almost $30,000 for Hurricane Katrina disaster relief. The money went
directly to the American Red Cross.
May God bless the efforts of you and your colleagues, Kris!
Warped
Universes, Warped Lives
-- Posted by wostraub on Monday,
September 26 2005
I've been in Dana Point for
several weeks sailing and just goofing off, but during this time I had the
opportunity to read Lisa Randall's fascinating new book Warped
Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions.
Randall is Professor of Theoretical Physics at Harvard University. A
Harvard PhD at 25, she's exceptionally intelligent (as well as young and
beautiful) and has some neat ideas to share, which is why she wrote the
book.
I'm thinking of writing and then posting a "book report" on this,
but we'll see about that. For now, I'll share an observation I've had for
some time about women scientists (hopefully you've already read my comments
about Emmy Noether).
When I was in physics graduate school, there was a fellow student I got to
know who was simply light years beyond everyone else. Angelyn was only 20
at the time (and also beautiful), but she knew ten times as much then as I
do now about quantum mechanics. She seemed to always know the answers, and
they came off the top of her head seemingly without any effort. She
finished her PhD in physics at UC Riverside, and is now a senior scientist
at JPL.
Later, a female civil engineer worked for me who likewise stood head and
shoulders above all the others in the office (she was also beautiful).
Julie had the highest GRE score of anyone I'd ever seen, and when she
decided to go to graduate school she was immediately picked up at Stanford,
where she received her doctorate a few years later.
(I could also add that my daughter Sheryl, a California attorney-at-law, is
also smart and beautiful, but I'm too biased to say it.)
It boggles my mind to think that Randall is almost certainly several orders
of magnitude beyond these gals. How can some women be so smart (and
beautiful)?
I think the answer lies in the fact that they're really no different than
men, at least intelligence-wise. I also think all this talk about male
mathematical/science superiority is a lot of nonsense. Women can do
anything men can do, and often better. They also seem much less prone than
men to start wars. [Note: I am not suggesting that Laura
"Stepford" Bush run for president, though she'd probably be an
infinitely better pick than her s**t-for-brains husband.]
In the introduction to Randall's book, she briefly describes how she became
hooked on science and her lifelong fascination with math and physics. I
think that's all it takes -- a few brains, an unquenchable curiosity of the
world we live in, and a burning desire to understand it from first
principles (this is almost a direct quote from Einstein). It's a shame that
great women scientists like Noether, Lise Meitner, Rosalind Franklin and
scores of others were denied Nobel Prizes and other honors simply because
of their sex.
In closing, I can't help but make an additional (though negative) comment
pertaining to female achievement, as I feel it's very appropriate. Dana
Point, California is a beautiful place, but it's marred by legions of idle
"Orange County women" whose goals in life seem to revolve around
shopping, beauty parlors, constant cell phone use, and the acquisition of
expensive cars and homes -- all on a middle-class income. In Orange County,
they justify these excesses by calling them "family values."
Enough said, I'm in trouble now!
Weyl's
Theory and Early Quantum Theory -- Posted by wostraub
on Wednesday, September 21 2005
Weyl's 1918 gauge theory
essentially stated that the magnitude of a vector quantity was not absolute
but variable from point to point in a 4-dimensional manifold, and that the
electromagnetic four-vector was responsible for this variability. Einstein
at first lauded Weyl's idea, but then realized that time, not just length,
would also be variable. Einstein noted that time would then depend
upon a particle's history, and that atomic spectral lines (which are fixed)
would vary from atom to atom depending upon their individual histories.
Correspondence between Weyl and Einstein on this point has been preserved,
and it shows how desperate Weyl was to reclaim his theory despite the fact
that Einstein was obviously correct. Out of his desperation, Weyl suggested
that particle time and position were in some sense unobservable,
and he briefly postulated that his gauge theory was correct after all and
that certain gauge-affected observables (like time) required a more general
definition. Of course, it was all nonsense.
Or was it? Weyl's basic idea was that Nature employs a gauge symmetry in
which a rescaled metric tensor does not affect any essential physics:
$g_{\mu \mu} --> \lambda(x) g_{\mu \nu}$
where $\lambda(x)$ is an arbitrary function of spacetime. Of course, the
components of the metric tensor $g_{\mu \nu}$ are real and observable.
As is well-known, Weyl's theory was reinvented as the phase invariance
concept of quantum mechanics, perhaps the most profound symmetry known in
modern physics. Weyl's gauge theory works in QM precisely because the wave
function is unobservable and can involve an arbitrary phase function.
My contention is that Weyl's original gauge idea didn't work only because
the metric tensor is a real, observable quantity, and that Weyl actually
anticipated the existence of the wave function eight years prior to
Schrodinger's celebrated wave equation. After all, it was only one year
after the 1926 wave equation that physicists (including Weyl, London, and
even Schrodinger himself) began to realize that Weyl's gauge concept was
workable in QM and that it was in fact required in order to incorporate
electrodynamics into the then-developing quantum theory.
Amalie's
Ashes -- Posted by wostraub on Tuesday, September 6 2005
This year marks the 70th
anniversary of the death of Amalie (Emmy) Noether, colleague of Weyl,
Einstein and countless other great 20th-century scientists, and generally
regarded as the greatest female mathematician who ever lived.
I just finished reading a chapter on Noether in Nobel Prize Women in
Science: Their Lives, Struggles, and Momentous Discoveries, Second
Edition, J.H. Henry Press (1993). I realize now that I did not give her
adequate credit in my little write-up (see Weyl & Higgs), and
I now stand in awe of the woman, both in terms of her gifts as a
mathematician and as a human being.
In spite of the harsh, ongoing prejudice she experienced firsthand even as
one of Germany's top mathematicians in the teens and 1920s, Noether
doggedly pursued her field with little or no regard for her own well-being.
In recognition of her greatness as a mathematician, she was invited by
Hilbert and Weyl to teach at the University of Gottingen. But for many
years she was an unpaid, untenured, unpensioned nichtbeamteter
ausserordenticher Professor, which roughly translates to
"unofficial, unprivileged third-class instructor" (not unlike
adjunct faculty!) Out of a total faculty of 237, Noether was one of only
two female professors at the school (the other was a physicist).
As I mentioned in my earlier write-up, Noether was a pacifist, left-wing
Jewish female, and these traits did not endear her to the Nazis. When
Hitler was appointed Chancellor of Germany in January 1933, Noether was one
of the first professors to be fired. She and numerous other colleagues at
the University of Gottingen tried to hang on, but brownshirted Nazi
students successfully boycotted her and other Jewish professors -- “Aryan
students want Aryan mathematics, not Jewish mathematics!.”
Denied of a livelihood, Noether (with the assistance of Weyl) formed the
German Mathematicians’ Relief Fund, and for a while taught secretly
from her apartment.
Even Weyl (a Christian) was forced to leave, as his wife was a Jew. Moving
to the Institute for Advanced Study in Princeton in 1933, Weyl mourned the
resulting Nazification of science and mathematics and witnessed the
destruction of German preeminence in science, philosophy, psychology and
mathematics with a broken heart.
In 1933, Noether too fled, to Bryn Mawr College in Pennsylvania, where she
was given a limited professorship at three-quarters pay. She died there in
1935 following the surgical removal of a large ovarian cyst. Although the
college neglected to preserve her papers, it did manage to preserve her
ashes. In 1982, on the centennial anniversary of her birth, the school
buried her ashes under a brick walkway near the library’s cloisters.
I see a terrible parallel to the madness Noether faced in Germany with
events in this country today: anti-intellectual, fundamentalist fervor is
demonizing stem-cell research and evolution (even geology) in favor of
mystical, irrational, evangelical creationist theories, including
“intelligent design.” Like the anti-intellectual, anti-feminist
Nazis, narrow-minded idealogues like Pat Robertson, Jerry Falwell and Bill
Frist are beating the drums for the destruction of modern science and
rational thought in America. In their foaming hatred of feminism, I hear
clear echoes of the words of Nazi Propaganda Reich Minister Josef Goebbels:
“The mission of women is to be beautiful and to bring children
into the world.”
In a recent issue of Physics Today, physicist Lawrence Krauss
addressed the lack of any contemporary Einsteins. Sadly, no one of the
moral and intellectual stature of Noether, Einstein or Weyl exists today.
No doubt, if these great people were alive now, they would be quickly
ostracized by the Bushies and their media whores as intellectual peaceniks.
They would also be ignored by the American public, which largely prefers
reality TV to reality.
Dirac's
Burial Plaque --
Posted by wostraub on Sunday, August
28 2005
Just thought I'd show this, which is located in Westminster Abbey, not far
from where Newton rests. This and Boltzmann's headstone are the only
markers I know of that celebrate great scientists with famous equations!
The grave of Boltzmann (who committed suicide in 1906) is honored with his
entropy equation S = k log W, while the above photo expresses
Dirac's relativistic electron equation, which is arguably the most
beautiful equation in physics. The "OM" stands for Order of
Merit, an honor that Dirac was particularly proud of. He was also
elected a member of the Royal Society in 1930 at the age of 28.
One of the utter shames of this world is that the average person has never
heard of Paul Dirac, whose name should be as well-known as Newton's and
Einstein's. For more information on Dirac and his equation, see my write-up
on Weyl spinors.
Weyl and
Overdetermination --
Posted by wostraub on Saturday,
August 27 2005
In one of my write-ups I
glossed over the fact that Weyl's theory of the combined gravitational-electrodynamic
field relies upon the square of the Ricci scalar, $R^2$. In terms of the
metric tensor, this quantity is of the fourth order in $g_{\mu
\nu}$ and its first and second derivatives. Einstein and many others
objected to Weyl's theory for this reason, since solutions of the Weyl
action tend to be overdetermined (i.e., non-physical "ghost"
fields can appear).
I've looked all over for a detailed response from Weyl on this issue.
Clearly, he understood its relevance yet he didn't seem to be overly
concerned about it. However, if you calculate the equations of motion from
the free-field Weyl action principle, you find that you can divide out an R
term (assuming it is a non-zero constant), which leaves second-order
equations of motion! I don't know if Weyl was aware of this or whether he
dismissed the overdetermination issue out of preference for the essential
beauty of his theory.
Nature seems to prefer second-order equations, whether one is dealing with
classical physics or quantum mechanics. There are exceptions, however. The
one that comes immediately to my mind (which any structural engineer will
instantly relate to) concerns the equations governing the elastic bending
of beams. Indeed, loaded beams are described by a fourth-order differential
equation. Fourth-order equations also result from perturbative expansions
in quantum mechanics, but these don't qualify!
Ghost fields in quantum mechanics are generally frowned upon. I've always
looked upon the scalar Higgs field as a kind of ghost field, but it results
from symmetry breaking rather than any inherent defect in the associated
action quantity.
The
Snapping of String Theory? -- Posted by wostraub
on Friday, August 5 2005
This month's Discover
magazine has an article by Michio Kaku on the future of string theory. Kaku
addresses the fact that string theory has now been around for over 35 years
without a shred of experimental evidence to back up the theory's many
predictions. He also recognizes the fact that most of the world's top
physicists seem to be gravitating toward string theory, thus depriving
other fields (notably particle physics) of upcoming talent. Many notable
physicists, including Lawrence Krauss and Sheldon Glashow, feel that string
theory is a mathematically beautiful but ultimately empty concept that
should be either verified once and for all or abandoned.
Kaku describes a few experiments that might provide some support for string
theory (involving dark matter, gravitational waves, and the Large Hadron
Collider), but for now the theory's only support seems to be its beautiful
mathematics. I for one disagree, because I feel that the math is just too
confounding (but I'm a mediocre hack, so who am I to judge?)
String theory verification may ultimately require energies that are simply
beyond what mankind will ever muster. We can currently probe spacetime down
to a distance of around 10(-18) meter, but strings typically involve
distances a billion billion times smaller than that. What good is a theory
if it predicts structures and hidden dimensions that are on the order of
the Planck scale? We'll never get own that far!
It's too bad that Kaku's article wasn't handed to Scientific American,
which always goes into things much deeper than popular science magazines
like Discover. Popularized accounts of the quantum theory and
gravitation are rarely interesting nowadays, mostly because the mathematics
can be understood by undergraduates. But string theory is so damned confounding
that only experts can work in the field, and even they have confessed that
they don't know what the hell they're doing. Consequently, popularized
accounts of strings are so dumbed-down that they're essentially useless.
Kaku (himself one of the experts) is one of the better expositors, but his
article in Discover really doesn't tell me anything.
Weyl and
Higgs -- Posted by wostraub on Sunday, July 24 2005
Here's a very simple derivation
of the Lagrangian for quantum electrodynamics along with a description of
the Higgs mechanism (and why Weyl should get a lot of the credit for both
of them).
Net Energy -- Posted by wostraub on Tuesday, July 19 2005
The July 17 Los
Angeles Times Magazine ran a great article on the likely future of
hybrid cars, focusing primarily on rapidly-developing technologies will
allow these cars to be plugged in overnight to charge batteries, rather
than have the cars' own gas engines do the charging.
AeroVironment, a Monrovia, California company (www.AeroVironment.com) has
received a $170,000 grant to retrofit Toyota Prius hybrids with an
additional 180-lb battery pack that can be charged separately. Additional
tinkering with the car's electronic controls allows the car to run on
battery power only for the first 30 miles or so (I have a new Prius, and I
think this is a fantastic idea). Overall, the company's prototype Prius is
getting slightly over 100 MPG using the new system. While messing with the
hybrid energy drive voids the car's warranty, Toyota appears smitten with
the idea and has indicated a willingness to work with the company regarding
the warranty issue.
The article goes on to state that jazzed-up hybrid vehicles might soon
achieve up to 500 MPG and beyond. Great news, when gasoline is running
around $2.67 a gallon (at least here in Pasadena, CA).
However, that 500 MPG figure does not take into account the gasoline energy
equivalent to charge a hybrid's batteries off the grid. A more recent
article, put out by the Environmental News Network, demonstrates that the
net energy output of a system needs to take such things into account. This
is especially true when considering the production of ethanol from corn,
which has lately been widely touted as a cost effective new gasoline
additive.
The article states that researchers at Cornell University and the
University of California at Berkeley have concluded that it takes 29
percent more fossil energy to turn corn into ethanol than the amount of
fuel the process produces. Similarly, it requires 27 percent more energy to
turn soybeans into biodiesel fuel, while more than double that to do the
same to sunflower plants, the study found.
"Ethanol production in the United States does not benefit the nation's
energy security, its agriculture, the economy, or the environment,"
according to the study by Cornell's David Pimentel and Berkeley's Tad
Patzek. The universities concluded that the country would be better off
investing in solar, wind and hydrogen energy.
The researchers included such factors as the energy used in producing the
crop, costs that were not used in other studies that supported ethanol
production, and they also took into account some $3 billion in omitted
state and federal government subsidies that go toward ethanol production in
the United States each year.
Believe me, I'd love to see America producing cars that get 100 MPG, and I
sincerely think it's technologically possible. But like all things, let's
consider the whole picture before we get too optimistic.
More
Fizzicks Fun --
Posted by wostraub on Monday, July
18 2005
You gotta just love the
new Hewlett-Packard Pavilion notebook computer commercial.
The setting is a university lecture hall. A physics professor is droning on
monotonously (a la Ben Stein as the teacher in "The Wonder
Years") on atomic physics. The cute young thing in the front row is
busy with her new HP Pavilion computer, but she's not taking notes -- she's
watching DVD videos, including tattooed rock singers who
magically jump out and writhe suggestively on her desk, obliterating the
boring physics lecture.
Remember Malibu Stacy's response to a Simpson's math question? "Don't
ask me -- I'm only a girl (tee hee)!" Ms. Stacy must be HP's target
demographic.
No wonder America's students are going down the drain in math and science.
If a student of mine had acted like this, I'd have kicked her out of the
class forthwith (and probably gotten myself fired in the process).
Earlier I gave a bad review of Tom Friedman's new book The World is
Flat, but one of the book's many good points is that it accurately
assesses the awful state of math & science education in the United
States and how we are being rapidly being taken over academically by other
countries, notably China.
Hewlett-Packard is a high-tech US firm. What in hell are they doing putting
out ads like this?!
Update 19 Jul 2005 HP announced this morning that it would lay off
14,500 workers and freeze employee pensions. Guess the commercial's not
working.
Speaking
of Uranium -- Posted
by wostraub on Saturday, July 16
2005
I've always been
fascinated with heavy metals. As a kid, I used to play around with mercury (warning:
it's very toxic, and has a relatively high vapor pressure, so don't mess
with it!), rubbing it onto silver coins to make amalgams (this was
pre-1964), mixing up explosive fulminates for fun (I still have all ten
fingers and two eyes, thank the Lord), or just being awed by its
"divine heaviness" (to quote Auric Goldfinger).
There are other neat heavy metals. Platinum is pretty dense; gold somewhat
less so. Neater by far is iridium, which is reasonably safe and
even more divinely dense than gold, and another is osmium, which
is arguably the densest stable element in nature, although it has a nasty
habit of erupting into flames in the presence of oxygen and giving off
toxic fumes of osmium tetroxide. Still another is gallium,
although its main claim to fame is not density but its tendency to melt in
your hand (unlike M&Ms). Alas, outside of the Exploratorium, Los Alamos
or Sandia Labs, you're likely never to heft a sample of iridium or osmium
or gallium, so mercury remains the poor man's (or kid's) heavy metal of
choice.
But every kid's holy grail, at least when I was growing up, was uranium.
To this day I have never held any, though I've seen samples behind glass.
I've heard that enriched uranium is actually warm to the touch (and
plutonium even more so), but despite its inherent dangers I've always
wanted to own some, maybe as a paper weight. U-238 is used as cladding for
armor-piercing artillery; there's a lot of it lying around in Iraq now,
though most of it has probably vaporized. Depleted uranium poisoning is a
candidate cause of Gulf War Syndrome.
Like all elements past bismuth in the periodic table, uranium is
radioactive. It occurs naturally in isotopic form, mainly U-238 (the most
common and boring variety), followed by U-235 and U-234; only U-235 is
fissionable. Uranium can actually be mined; because U-238 has a half-life
of about 4.5 billion years, there's still enough of it in the earth's crust
that it can be mined economically. About 0.7% of what's mined consists of
the isotope U-235, and this is where humankind gets its nuclear fuel (and
bomb material). Plutonium-239 cannot be found in the elemental or
chemically-bound state, but it can be made by transmuting uranium via
neutron bombardment. Every garden-variety nuclear power plant is in fact a
plutonium factory. Pu-239 is also fissionable, and has several advantages
over U-235 in terms of bomb potential. If you can manage to fashion a
sphere of Pu-239 metal about 5 inches in diameter, you'll have a critical
mass of the stuff (but you won't have it for very long).
The density of mixed uranium metal is about 19.05 g/cc, somewhat less dense
than gold and about 15% less dense than osmium or iridum, but much more so
than mercury (13.6 g/cc). People who have actually hefted a chunk of the
metal have stated that it seems almost unreal.
Now for the point of all this. When God created the universe, he allowed
nature to make all kinds of elements, but only one fissionable variety that
could be mined in quantity. In my opinion, without U-235 and its 0.7%
concentration in mined uranium metal, thermonuclear weapons would probably
never have come into being. What was God's reasoning behind all this?
He may have provided it as a means of giving mankind a source of long-term
energy, one that would last far longer than the all too-finite resources of
the fossil fuels we're rapidly depleting. Or he could have placed it on
earth as a means of ensuring Armageddon. Both possibilities seem to be
tailor-made for mankind, either in view of his need for energy, or his
assured destruction. I'm not thanking God or blaming him for this
situation; I'm just raising the issue.
Today, we have many thousands of megatons of thermonuclear weapons
stockpiled and ready to roll, whereas the peaceful uses of nuclear energy
are relatively insignificant. (Well, I guess Europe has a good deal of
nuclear power, but the United States, China, India and Russia still prefer
fossil fuel.)
I for one don't have a good feeling for where we're headed, but I have been
spectacularly wrong on lots of things. My advice: Continue to ask God for
his protection, guidance and salvation, and hope that some idiot like Bush
doesn't try to force Christ's return by blowing everyone up.
By the way, journalist Frank Rich of The New York Times has an excellent
article on uranium (hint: the Niger kind):
Also BTW: Has anyone read the book How to Survive the Coming Global
Thermonuclear Holocaust and Make a Stinking Profit to Boot (Republican
Neoconservative Press, 2005).
Goenner
Again -- Posted by wostraub on Thursday, July 14 2005
If you have any real interest
in physics, particularly its evolution from Einstein's geometrical approach
to quantum theory, you simply must read On the History of Unified Field
Theories by Hubert Goenner of the University of Gottingen. Pretty much
all of this involves the progress of theoretical physics from 1920 to 1929,
concluding with Weyl's historic 1929 paper on gauge symmetry. Of particular
interest are the efforts to to incorporate Dirac's relativistic electron
theory, which appeared in 1928, into Einstein's ideas of spacetime
geometry. Even the five-dimensional theory of Kaluza-Klein was given the
Einstein treatment, to no avail. By the end of 1929, it was all too clear
that Einstein's general relativity just did not mesh with quantum
mechanics.
I mentioned Goenner's paper earlier on this site. I finally finished
reading the whole thing, and I have to admit that he's got a lot more in
his one paper on Weyl than I have on my whole stupid website (at least he
doesn't seem to be adversely distracted by the Bush Reich, like I
am).
I cannot get over the sheer amount of intellectual effort that went into
the various attempts to reconcile gravitation with quantum theory, or the
optimism that reigned regardless of the fact that nobody really seemed to
know what was going on. I think it can be traced to the fact that there
were only two forces known at the time: gravitation, which was elucidated
by Einstein, and electrodynamics, which Weyl had seemingly unified with
gravity in 1918. In the end, neither could be reconciled with quantum
theory, at least in terms of what was known by the time the 1920s ended.
Part 2 of Goenner's excellent overview of unified theory is yet to come; I
welcome it enthusiastically.
World Oil
Production -- Posted
by wostraub on Sunday, July 10 2005
The attached link
summarizes world oil production data for the period 1860-2003, as obtained from
the US Department of Energy (Energy Information Agency). I assume it's
reliable, although the numbers are a tad higher than those given by
Deffeyes. My statistical analysis for the Gaussian regression is included;
the graphic shows the data (open circles) along with the superimposed
regressed normal distribution curve (grey line), which fits rather nicely.
However, note that, according to this analysis, Peak Oil occurred in 1998!
[Note: I used a non-linear multivariate regression program called NLREG to
do the analysis.] Obviously my preliminary analysis is not very realistic,
but it's intended only to get you thinking about the Peak Oil issue,
anyway. The actual situation is more complicated because it involves oil
reserves and discoveries (that may or may not be included in the EIA data)
and not just produce-and-use data. At any rate, this will give you some
idea of how the data are being viewed by a number of researchers (and many
of them are alarmed at what they're seeing).
One thing that is not in question is that once the oil production curve
starts to fall over from its exponential rise, the Peak Oil phenomenon will
be inevitable. This will then signal the end of cheap oil, the
commodity that runs the modern world. What will replace it? I haven't a
clue. God gave us something like 2 trillion barrels of oil, and we've gone
through about half of that. God's gift should have been used to develop a
more sustainable energy source (such as solar), but instead it went to
Hummers and their kin. Now it looks like oil wars are inevitable.
My advice is that you get up on the issue and decide for yourself.
Peak Oil -- Posted by wostraub on Wednesday, July 6 2005
Recently, I compiled a
table of world oil production data for the period 1860 to 2004 and did a
regression analysis on the data assuming a normal distribution (Gaussian)
model. I think I know why the Peak Oil doomsayers do not use this model.
Using a nonlinear regression program called NLREG for the Gaussian model,
my results show a decent data fit (the r^2 statistic is about 0.98) with a
standard deviation of approximately 25 years and a total production of
about 1.7 trillion barrels (this is the amount of oil contained in all the
planet's reservoirs). However, the peak year comes out to be 1998, seven
years ago! [This really isn't as embarrassing as it may seem, because
it's doubtful that any simple model will be within 10 years of the actual
peak, anyway.] Of course, oil production hasn't peaked yet, as far as we
know. For my pathetic little model, post-1998 oil production data overshoot
the model, but this doesn't necessarily mean it's wrong.
Most of the models I've seen use the logistic function, which is
often used in population projections. I have absolutely no idea why it
should be preferred over the Gaussian function for making oil projections.
The logistic models typically give the peak year at around 2005 to 2015,
with a total production of about 2 trillion barrels. Since these peaks are
in the future, maybe that's the reason.
I've found a way to express the data as a rate plot, a device that
Deffeyes explains in his excellent book Hubbert's Peak. It's
basically just an x-y plot using specially transformed data, which gives a
straight line. The x-intercept provides another method of obtaining the
total production. It too gives 1.7 trillion barrels.
What's not in doubt is the amount of oil we've burned since the famous
Titusville, Pennsylvania oil well started producing in 1860 (the "Ur
well" of the oil age). It's hard to believe, but humans really have
burned about half the oil that was formed in the earth over the past few
billion years. [Side note: I once asked a new-earth creationist friend how
all that oil got formed in just 6,000 years, since no chemical or physical
process known to man could have done it in that short of time. Her answer:
"God put it there for our use." May the Lord preserve us from
this incredible ignorance!]
While curve fitting is great fun, I'm trying not to take things too
seriously, at least not yet. Still, if there's any truth to this at all, it
portends a terrible future for mankind. The worst part of it is that it may
not be more than a few years away. Either way, we're not doing much about
it.
Dr. Albert Bartlett, Professor Emeritus of physics at the University of
Colorado at Boulder, has been warning us of the peak oil issue for many
years. He claims (and I believe he is correct) that one of mankind's
greatest failures is his unwillingness to appreciate (or even understand)
the exponential function. Because we tend to use untapped resources
initially at an exponential rate, we naively adopt the misconception that
unrestrained growth is always good and can be sustained indefinitely. To
me, that's one of the stupidest aspects of human beings -- we think only in
the short term and believe that God, technology or luck (or that old
standby, the "indomitable human spirit") will somehow bail us out
when things go to hell.
I'll put up what I have so far in a few days and you can decide for
yourself if world oil production is peaking.
Pauli -- Posted by wostraub on Monday, July 4 2005
I finally finished reading
Penrose's book (The Road to Reality), which is a remarkable text
in terms of the sheer amount of material it covers. It doesn't go into a
lot of detail, but if I were stuck on an uninhabited island somewhere I
would probably like to have it with me. Alas, I never quite got through
Zwiebach's A First Course in String Theory, despite a rather
gallant effort on my part. The math is not too difficult (remember, this is
a very introductory text), but the physical models it presupposes are
simply beyond my comprehension. Yes, strings are actually strings, but they
have this peculiar habit of attaching themselves to membranes in a
God-awful number of dimensions. What the hell are these membranes other
than highly-abstract boundary conditions? It's a right brain/left brain
thing, I believe, and I've been forced to grudgingly accept the very
serious limitations of my little grey cells, as Poirot puts it. Again, I
emphasize that this is an introductory text. Lord, is there any
hope for me?
So in utter defeat this evening I pulled down my crumbling Dover copy of
Pauli's Theory of Relativity, which always holds something that I
had overlooked the last time I got it down. Although I am enamored of Weyl,
his writing style (or at least the German translations of his writing) very
much leave something to be desired. In short, Weyl's ideas are beautiful,
but his writing is not, at least in my opinion. Pauli, on the other hand,
is a joy to read, at least the stuff I understand, and this is especially
true for his relativity book.
I may be stretching things here, but the book actually covers about 35
years of progress on basic general relativity. Pauli wrote the first
version in 1921 as a lengthy German encyclopedia article, then appended it
in the mid-1950s with supplementary notes. The book includes a section on
Weyl's theory of the combined electrodynamic-gravitational field, and as
such was only the second book I acquired that provided details on Weyl's
theory.
The book is a pleasure to read, from Pauli's clear exposition of special
relativity to general relativity and beyond. I was absolutely dumbstruck
when I learned that Pauli had written the book when he was only a 21
year-old graduate student. Talk about grey cells!
An oft-told anecdote about Pauli concerns his admittance to the hospital
for cancer treatment in 1958. His lifelong fascination with physics
included a similar fascination for the fine-structure constant of quantum
mechanics, which is very nearly the pure number 1/137. He always wondered
why God had created such a number. In quantum mechanics, constants tend to
be truly microscopic (Planck's constant is about 6 x 10^-34, for example),
so the appearance of a number that is about 0.008 boggles the mind. What
also boggles the mind is that Pauli, who passed away in the hospital at the
relatively young age of 58, died in Room 137. Don't ever think that God
doesn't have a great sense of humor!
Every high school student gets introduced to Pauli through his Exclusion
Principle in chemistry. But the man was such a gigantic figure in the field
of physics that he deserves so much more. He was an irrascible and impudent
curmudgeon who was famous for his crushing verbal put-downs of lesser
physicists who dared to expose their ignorance, but he could also be caring
and supportive. He was fond of Weyl and truly loved Einstein, despite the
great scientist's ill-fated rejection of quantum mechanics.
The Dover book is still available as a paperback for maybe $10. I heartily
recommend it.
Weyl and
Chalabi -- Posted by wostraub on Saturday, June 25 2005
You cannot apply
mathematics as long as words still becloud reality. -- Hermann Weyl
I don't know what context Weyl intended in this quote, but I'm tempted to
think that he saw empty rhetoric as the enemy of truth and reason.
You cannot lie with mathematics because you will quickly be found out. It
is far easier to lie with words, because until someone can check out what
you're saying (which may not even be possible), people have to assume that
you're telling the truth.
Mathematics and words both come from the heart, but only one is required by
its own nature to be true. It is true that one can lie with statistics, but
the lie is sold through the interpretation of the meaning of the numbers,
which gets us back to words again.
Jesus Christ warned us to be careful about what comes out of our mouths,
but it wasn't mathematics he was concerned with.
Most people are not aware that years ago, the designated Iraq Minister of
Oil Ahmad Chalabi was a professor of mathematics at the American
University of Beirut, Lebanon. The son of a wealthy banker, Chalabi studied
at MIT and the University of Chicago, where he received his PhD in
mathematics in 1969 (I believe his specialty was ring theory). Of course,
you're certainly aware that Chalabi, an Iraqi Shi'a Muslim, is a notorious
liar who stuffed Bush's head full of lies (as if it wasn't already full of
them) about Iraq's non-existent weapons of mass destruction. He is also
under warrant for arrest in Jordan for embezzlement and money laundering.
After all of his "disassembling," Chalabi still managed to
wrangle the job as oil minister on the new Iraqi cabinet, largely on the
basis of his ongoing connections with Bush, the CIA, and the Pentagon. He's their kind of people!
This serves to show that while mathematics doesn't lie, mathematicians
certainly can.
My guess is that Chalabi will be assassinated when the Bush administration
begins to siphon off large quantities of oil from the Iraqi oil fields to
supply all the military bases we're constructing in that country. He
certainly doesn't have the interests of the Iraqi people at heart, and his
role as a Bush oil puppet is certain to get him into trouble. Before he
dies, I hope the last thing that goes through his head (other than a
bullet) will be the sincere regret that he didn't stay in mathematics.
Sorry that I mentioned Weyl and Chalabi in the same breath; Weyl deserves
better.
Grace S.,
1924 -- Posted by wostraub on Friday, June 24 2005
Here lies a most
beautiful lady:
Light of step and heart was she;
I think she was the most beautiful lady
That ever was in the West Country.
But Beauty vanishes; Beauty passes;
However rare -- rare it be;
And when I crumble, who will remember
This lady of the West Country?
Epitaph, Walter de la Mare, 1873-1956
Weyl and
Philosophy -- Posted
by wostraub on Friday, June 24 2005
I have been having great
difficulty lately understanding Weyl. Not his physics (which is pretty
straightforward) nor his math (which can be exceedingly difficult for a non-mathematician
like me), but his extensive philosophical writings.
During his life, Weyl went through various stages of philosophical
speculation. Each was important to him in its own time, as Weyl aged and
became wiser, from phenomenology to what might be called religious
existentialism. He consequently devoted an enormous amount of time and
effort to philosophy, no doubt a result of his deep reflections on the
interconnectedness of mathematics, physics and the human mind.
Unfortunately for me, I'm having one hell of a time understanding Weyl's
philosophical musings. I'm inclined to state that he is very deep, but at
times it all seems like a bunch of mumbo jumbo. The same thing happened
when I tried to learn category theory, which has been described as
both the fundamental basis of all profound mathematical theories and
"generalized abstract nonsense." Being trained neither in formal
mathematics nor philosophy, I'm at a distinct disadvantage to criticize
(never mind fully comprehend) Weyl's efforts in either field. But I keep
trying.
In 1954, near the end of his life, Weyl reflected on what he had learned
over the years in physics and philosophy, as necessarily colored by two
world wars in which his native country, Germany, had participated in rather
shamefully:
"I did not remain unaffected either by the great revolution which
quantum physics brought about in natural sciences, or by existentialist
philosophy, which grew up in the horrible disintegration of our era. The
first of these cast a new light on the relation of the perceiving subject
to the object; at the center of the latter, we find neither a pure
"I" nor God, but man in his historical existence, committing
himself in terms of his existence."
This is the philosophical Weyl that I can relate to.
No Weyl in
Pasadena -- Posted by
wostraub on Monday, June 13 2005
Well, I tried. This was
the response I received from the Institute for Advanced Study:
Dear Dr. Straub:
Thank
you for your inquiry to the Archives of the Institute for Advanced Study. I
have searched the documentary evidence that we have for mention of any
visits by Professor Weyl to Caltech. I'm sorry to report than I find none,
though there is other travel documented, including west to Colorado, where
Professor Weyl apparently went to escape allergies that plagued him in New
Jersey. From my review of the literature, he seems to have been a reliable
presence on the Institute campus during the academic year, and regularly
gave lectures here. Of course, that does not preclude a brief trip here or
there, and his summers were his own. I have searched for literature you
might consult to advance your research, but don't find anything to add to
what your website indicates you've already seen. I'm very sorry not to be
able to be of more help, but I will keep your inquiry in mind, and be in
touch if I find anything that might be of interest to you.
Regards,
Erica
Mosner Library
Assistant Historical
Studies-Social Science Library Institute
for Advanced Study Einstein
Drive Princeton,
New Jersey 08540
Thanks, and God bless you, Erica!
Weyl in
Pasadena? -- Posted
by wostraub on Saturday, June 11
2005
I recently contacted Dr. Judith
Goodstein at Caltech to see if Hermann Weyl had ever visited the school.
Goodstein is the University Archivist and author of Millikan's School,
a history of Caltech, and co-author (with husband and fellow Caltech
professor David Goodstein) of Feynman's Lost Lecture, so if anyone
can help me, I thought she could. Although Weyl went to the Institute for
Advanced Study (IAS) in Princeton when he left Germany in 1933, I figure
that his wanderings over the the years must have brought him to Pasadena at
least once.
Unfortunately, Goodstein told me that Caltech has no record of any visits
by Weyl. She suggested that I contact the IAS to see if anyone there keeps
a listing of Weyl's domestic travels. I'm in the process of doing that, and
will pass along whatever I find.
Jesus on
Truth and Lies --
Posted by wostraub on Thursday, June
9 2005
From John 8: 42Jesus said to them, "If God were your Father, you would
love me, for I came from God and now am here. I have not come on my own;
but he sent me. 43Why is my language not clear to you? Because
you are unable to hear what I say. 44You belong to your father,
the Devil, and you want to carry out your father's desire. He was a
murderer from the beginning, not holding to the truth, for there is no
truth in him. When he lies, he speaks his native language, for he is a liar
and the father of lies. 45Yet because I tell the truth, you do
not believe me! 46Can any of you prove me guilty of sin? If I am
telling the truth, why don't you believe me? 47He who belongs to
God hears what God says. The reason you do not hear is that you do not
belong to God."
Why doesn't America truly follow Jesus? Why are we embracing the torture
and imprisonment of innocents? Why are we spending half a trillion dollars
annually on weapons of death and destruction? Why are we throwing away our
Constitutional rights? Can't we recognize hypocrisy when it stares back at
us in the mirror? Why are we following the Devil?
Science
and Patriotism --
Posted by wostraub on Monday, June 6
2005
Johannes Stark was a
great German scientist who won the 1919 Nobel Prize in Physics for his
discovery of the "Stark effect," the splitting of atomic spectral
lines by electric fields. He was a prolific researcher who published over
300 scientific papers in his lifetime. He was also a fanatical German
patriot who early on embraced the Nazi belief that Jews were inferior human
beings. He became a member of the Nazi Party in 1930.
Stark was a strong proponent of "Deutsche physik," or Aryan
physics, which be felt should be used solely for the purpose of advancing
national defense and prestige. By comparison, he scorned what he termed
"Judische physik" (Jewish physics) on the basis that non-Aryan
physics was not scientifically objective (by this I suppose he meant that
physics was not objectified unless it had a nationalistic purpose). In
1934, Stark wrote a book, "National Socialism and Science," in
which he explained his views (I am going to read that book). He hated
Einstein and was no friend of the loyal (but not rabid) German physicist
Werner Heisenberg, whom Stark referred to as a "white Jew." In
1947, a court sentenced Stark to four years in prison for his contributions
to anti-Jewish hatred before and during World War II.
Stark's is a classic case of scientific inquiry gone mad. Pure science and
mathematics are completely objective when their pursuit involves
discovering the truth. I will take that statement one step further by
adding that objectivity cannot exist when a political agenda is attached to
the research. The most heinous example I can think of involves the research
and development of weapons of mass destruction for purely military and/or
political purposes. But a more common example would be the selective and
deliberate misrepresentation or skewing of scientific data for the purpose
of convincing someone that something is true when in fact it is not.
But Stark, Phillip Lenard and other noted German scientists first had to
convince themselves that Einstein's theories were wrong before they could
convince others. How did they do that? Einstein wasn't right about
everything, but his special and general relativity theories were thoroughly
tested and found to be valid. Also, these theories were, as Paul Dirac once
put it, mathematically "beautiful" (and they are). I believe that
this is where ethnic and political hatred made their way into the picture.
Stark believed that Einstein was of an inferior race, so his ideas had to
be wrong. This was no small effort -- he almost had to convince himself
that 2+2=5 in order to erase the truth of relativity from his mind.
Fortunately for Stark, he easily found others that shared his Nazi mindset.
Einstein's works quickly found themselves among the thousands of other
papers and books that the Nazis burned during Hitler's reign.
My younger son and I discussed a related topic today. I asked him why a
seemingly-disproportionate amount of funding is being spent on HIV/AIDS
research today. My straw-man argument was that AIDS is primarily a
behavior-related disease while, say, malaria threatens everyone, so why not
stress the preventive aspects of HIV. His response is that the human immunodeficiency
virus is a threat to mankind simply because it now affects so many people.
He felt that dwelling on issues like behavior-based prioritization of
funding is too closely tied to moralizing, which is subjective.
Subjectivity is the enemy of science and mathematics. It is also, sadly, a
very human trait.
I see the same thing happening to science today, and it is truly
frightening. HIV/AIDS, evolution and cellular research are all being
attacked on the basis of subjective moral and political arguments that have
nothing to do with the scientific method. The Dobsons, Frists, and Falwells
of this country fervently believe that HIV/AIDS is a punishment from God
designed to strike down immoral people. They have forgotten that when God
warned us "the wages of sin is death" he was referring to all
sin, not just homosexual sin (and yes, I do believe it is a sin). If I look
at a woman the wrong way, I have committed a sin that can put me in hell
along with every other unforgiven sinner; will I then feel somehow more
"sanctified" than the other lost souls?
Because they demand logical, organized and rational thinking, science and
math are giving Americans fits these days. Although we have some great (and
objective) expositors like Weinberg, Kaku, Lederer, Davies, Hawking and
Penrose around to explain things, we also have idiots like Dr. Frist whose
subjective pseudo-science represents an enormous threat to America. I'm
sure he's already compiled a long list of books that he plans to have
burned when he's president. God save us!
I hope he and his ilk can be stopped in time, but I truly fear for the
scientific future of this country.
"Rods
from God" --
Posted by wostraub on Thursday, June
2 2005
"Full-spectrum dominance."
That's the term the US military is using to describe a proposed planet-wide
system of nuclear-tipped intercontinental ballistic missiles and orbiting
weapons utilizing what insiders call "Rods from God." RFGs are
heavy metal cylinders that would be fired from orbiting space platforms to
take out enemy fortifications on earth's surface. The rods would be made
from dense metals like depleted uranium or tungsten and fired at such high
velocities that they could penetrate many meters of soil and concrete.
However, a half-dozen distinguished scientists, including Nobel prize
winners Steven Weinberg (physics) of the University of Texas at Austin and
John Polyanni (chemistry), professor at the University of Toronto, claim
that the proposed defense system would be a "criminal" waste of
hundreds of billions of dollars that would be better spent on public
welfare programs. They go on to say that the system would be unworkable
anyway and would offer only the illusion of absolute security if deployed.
Weinberg is the author of an excellent book on the general theory of
relativity and a three-text series on quantum field theory. The latter is a
tough read, but Weinberg's response to the RFG proposal is easy to
understand -- assuming that you're sane.
RFG represents only one facet of Bush's "space exploration
program." Of course, conservative faith groups are ecstatic over the
proposal because it has the word "God" in it. Also, they don't
generally trust math and science, because it's hard to understand and
promotes stuff like evolution and all, but "Rods from God" has a
nice Christian ring to it. Just the thought of evil doers being righteously
blasted to smithereens warms their hearts.
But the proposal has another, equally ominous aspect. Imagine you're the
leader of a nuclear country like Russia or China (or even France). You see
the United States being led by dangerous "Christian" fascists
determined to take over the earth and enslave countries owning the
resources needed by the United States to maintain its preposterous standard
of living. What have you got to lose? In coordination with the other
nuclear members, you fire off everything you've got, and hope for the best.
It's madness, of course, but it would at least guarantee the destruction of
the United States as a functioning society.
Is this the American Taliban's real game plan -- to provoke a worldwide
nuclear Armageddon and thus force Jesus Christ to make an early return?
Early
Unified Field Theory and the Quantum -- Posted by wostraub
on Wednesday, June 1 2005
I’ve been reading
lately about the efforts of Einstein, Weyl, Rainich, Eddington and others around
1925 to find a unified theory of gravitation and the electromagnetic field.
To my mind, these guys were the flip side to Bohr, Dirac, Pauli, and Fermi,
who of course were almost solely focused on quantum physics at that time.
In my opinion, Einstein’s discovery of general relativity in 1915
came at a really bad time. When the theory was brilliantly confirmed by the
explanation of the perihelion shift of Mercury and the solar eclipse
expeditions of 1919, there was no doubt whatsoever that general relativity
was a valid description of spacetime physics. In those simple days, the
only known forces of nature were gravitation and electrodynamics, and the
only known particles were electrons, protons and photons. Following the
brilliant but failed “near miss” of Weyl’s theory in 1918
and Rainich’s subsequent discovery of the algebraic similarities of
gravity and electromagnetism, Einstein and his colleagues must have felt
that a consistent unified theory was imminent.
However, the theory stubbornly resisted discovery. In hindsight, we know
that Einstein and the others were doomed to failure. Nature is not as
simple as Einstein had presumed; instead, it hosts a dizzying array of
elementary and composite particles, forces and fields requiring a much more
sophisticated physical and mathematical approach.
I get a real kick out of reading Einstein’s correspondence to the
other early field theorists of that time. One idea after another is
proposed – distant parallelism, bivectors, n-beins, a generalized
(and traceless) Einstein tensor – and each one is subsequently tossed
aside. Einstein constantly refers to the sublime secrets of nature and
“the Old One,” and on occasion waxes quite philosophic about
the nobility of the search. In spite of the failures he is not discouraged,
and continues to press on. Most of his colleagues, however, begin to
realize that it is probably a waste of time, and so they move on. But even
as late as 1929, rumors spread that Einstein had finally achieved his goal.
Several newspapers even printed the theory with all its mathematics for
their undoubtedly puzzled readers. It was all a big fuss over nothing.
By comparison, the development of quantum mechanics in the 1920s was met
with one astonishing success after another. I’m inclined to feel that
Einstein’s eminence in those years ultimately hurt physics, because
his unification efforts were sidetracking himself as well as the talents of
numerous great colleagues. Remember that when Einstein’s general
theory appeared, about the only quantum theory that existed was that of
Bohr’s hydrogen atom, which even then was seen as a hodgepodge of
classical and quantum ideas. It wasn’t taken seriously until
Heisenberg’s matrix mechanics and Schrödinger’s wave equation
arrived in 1925, and it was about that time that real interest in unified
theory was on the wane.
Today, physicists are hard at work on unified theories that Einstein
couldn’t have comprehended. String theory made its appearance in the
1970s, followed by supersymmetry, supergravity, superstrings, M-theory, and
loop quantum gravity. Recall Einstein’s initial support of
Kaluza-Klein theory in the 1920s, which sported a total of five spacetime
dimensions. Would Einstein have been equally enthusiastic about ten, eleven
and even twenty-six dimensions? I wonder.
To my mind, God displayed a wonderful sense of humor when he let Einstein
discover general relativity theory in 1915. God knew that scientists would
initially think they were close to knowing everything. At about the same
time he opened our eyes to quantum physics, and then probably watched with
much amusement as we tripped over ourselves trying to sort things out. But
eventually we did -- thanks to these wonderful, curious minds God gave us.
Einstein once famously remarked that “God is subtle, but not
malicious” (Raffiniert ist der Herrgott, aber boshaft ist er nicht).
Recently, a noted physicist (darn it, I just can’t remember the the
guy’s name offhand) dared rephrase Einstein’s remark as
“God is not malicious, but he is subtle.” This makes much more
sense to me. The maddening complexities of modern unification theories are
all too real, but they follow a kind of simplicity involving spacetime
symmetries and their evil cousins, the internal symmetries. Surely, this is
what God had in mind for mankind – we’ll try our damnedest,
but, even if we never find the true unified field theory, we’ll have
glimpsed God’s glory along the way.
And this would have surely pleased Einstein.
A
Lagrangian for Evolution? -- Posted by wostraub
on Thursday, May 26 2005
I was talking to my son
the other day about Lagrangians and the action principle in physics.
Lagrangians are mathematical quantities (usually integral scalar densities)
that, when extremalized, define the actual dynamical path that a particle
or wave function takes under a given set of conditions. These paths
generally result when something like energy or time is minimized. William
Hamilton was the first to formalize the mathematics (Hamilton's Principle),
although Fermat knew about the minimum-time principle of ordinary light
propagation. Because minimal principles represent the most efficient or
"best" ways that Nature can conduct her business, many early
scientists saw this as direct evidence of God's existence, and many still
do.
Lurking behind the Lagrangian formalism are mathematical symmetries. A
symmetry is simply a modification in a Lagrangian quantity that leaves the
quantity unchanged. For example, translation symmetry (the requirement that
physics be the same on Earth as it is on some extragalactic planet) leaves
the Lagrangian mathematically unchanged. I won't go into it, but this
symmetry is also responsible for the conservation of linear momentum. There
is a very powerful theorem (by Emmy Noether) which states that for every
Lagrangian symmetry there is a corresponding conservation law. It was Weyl,
in 1929, who showed that the conservation of electric charge is due to
gauge symmetry, which was a brand new kind of symmetry in those days. Since
symmetry is a form of beauty (and it may even be a definition of beauty),
one may indeed argue that God is behind all of this.
Now switch from physics to molecular biology. Is there a minimal principle
behind biological processes? Most certainly, because the behavior of
biologically-important molecules (proteins, enzymes, etc.) is governed by
quantum mechanics, and QM itself follows Lagrangian principles.
But what about large-scale biological processes such as genetics and evolution
(or, if you prefer, random mutations over large time scales)? What minimal
principle could possibly result in the formation, adaptation and
maintenance of complex living systems? Given a supply of simple organic
compounds, is life inevitable? Was the formation of the first RNA or DNA molecule the result of God or Nature minimizing
something? And if so, what was the driving force or symmetry behind it?
My argument with my son was that living systems today are so unbelievably
complex that concepts such as driving force and symmetry are totally hidden
from us. When physicists conduct particle collision experiments, they now
have a large collection of theoretical tools that they can use to design
the experiments and interpret the results. By contrast, for living systems
scientists can only watch and maybe make educated guesses. There are no
readily-apparent symmetries or driving forces that can be utilized to
interpret what they see. No one asks "Why are there proteins?" or
"Why did Nature decide to develop this kind of enzyme for liver
function?" When my son conducts PCR experiments or sticks mutated plasmids into
cells, all he can do is say "Let's see what happens."
I happen to believe that God created life. I also believe that he created
evolution so that life could adapt to changing environmental conditions.
But how he did all this is a great mystery (maybe so is why he did it). But
seeing God's penchant for symmetry in physical laws, my guess is that he
employed a similar approach when he designed life.
When I was very young, I remember asking my father why a flower grows. What
does it think it's doing? Why doesn't it just fall apart? Why should it
make other flowers? What's the purpose behind all this? In later years I
learned about things like Gibbs free energy, the equilibrium driving force
behind Newton's law of cooling, statistical mechanics, and the action
principle. But these revelations told me nothing about why God did what he
did, or why he used the approaches he did.
At the same time, I very strongly believe that our striving to answer these
questions is one of the principal reasons why God put us here in the first
place. When we finally figure it out, we'll know for sure what a great guy
he is.
The computational physicist Kent Budge has a blogsite (Trolling in Shallow
Water) that includes a rather off-beat look at God, Lagrangians, and why
Jesus was needed. Odd, and probably not what God actually had in mind, but
it's worth a look (it's near the bottom of the first page):
http://shallows.blogspot.com/2005/02/u1xsu2xsu3-part-2.html
John
Baez's Website --
Posted by wostraub on Sunday, May 22
2005
I've added a link on the
menu for the website of John Baez, professor of mathematical physics at the
University of California at Riverside. He specializes in quantum gravity,
but the guy seems to know about everything. His site has a lot of neat
stuff ranging from very easy to way over my head. His enthusiam is
contagious. Give him a look.
Einstein
on Nationalism --
Posted by wostraub on Saturday, May
21 2005
Einstein hated militaristic
nationalism. He would have undoubtedly deplored living in America at this
time, and would have certainly detested our pathetic Cowboy President, his
love of war, and his pro-torture position on innocent foreigners and
"enemy combatants." In reaction to his views, the Daughters of
the American Revolution (which until recently excluded all minorities from
its nobel ranks) told Einstein to get out of America. The House Committee
on Un-American Activities (McCarthy's little band of Nazis) similarly
denounced Einstein, and the cross-dressing transvestite J. Edgar Hoover had
his FBI compile a huge dossier on the scientist.
The attached Word file is a copy of a hand-annotated speech that Einstein
gave in May 1947 (I believe to the Emergency Committee of the Atomic
Scientists). Read it and ask yourself if these are the words of a dangerous
mind.
http://www.weylmann.com/einsteintalk.doc
Weyl and
Petrarch?! -- Posted
by wostraub on Friday, May 20 2005
Did you ever glimpse
someone, perhaps only for a moment, but it changed your life forever, and
for the better? Did you ever have one of those “Aha!”
experiences or a “Road to Damascus” moment that had the same
effect? In the following I present some random thoughts I’ve had
about Weyl and Beauty; it might even make for a passing grade on a high
school composition.
Her name was Laura de Noves, and she lived and died almost 700 years ago.
She was exquisitely beautiful, and when he was twenty-three the great
Italian humanist Francesco Petrarcha (better known as Petrarch) caught
sight of her at the Church of St Clare in Avignon, France. Although he saw
her for only a few moments, he fell into lifelong love with her. This was reportedly
the only contact he ever had with the woman. Yet she was his livelong
inspiration and the true force behind all of his great writings, including
his Canzoniere, his barely-concealed lyric poems in praise of Laura.
In the great Orson Welles classic, Citizen Kane, the elderly attorney
Bernstein has a similar story to tell to the shadowy Reporter: “One
day back in 1896, I was crossing over to Jersey on the ferry. And as we
pulled out, there was another ferry pulling in. And on it there was a girl
waiting to get off. A white dress she had on. She was carrying a white
parasol. I only saw her for one second. She didn't see me at all. But I'll
bet a month hasn't gone by since that I haven't thought of that
girl.”
And one cannot even mention the great Italian renaissance poet and writer
Dante without conjuring up the memory of his beloved Beatrice. It is this
Beatrice, who Dante saw once and remained forever in love with, who guides
Dante to Paradise from the depths of Inferno and Purgatorio. Like Laura’s
influence on Petrarch, Beatrice was the inspiring force of Earthly beauty
that compelled Dante to seek out truth, God and salvation. His Divine
Comedy is considered by many to be the greatest literary work ever.
Finally, the noted Austrian physicist Erwin Schrödinger, while on an
extramarital fling in the mountains in 1925, came up with his greatest
discovery, the aptly-named Schrödinger wave equation, for which he shared
the 1933 Nobel Prize in physics. Who was the unnamed lady (if she can be
called that), and just how did she inspire Mr. Schrödinger? Nobody knows.
What does all this have to do with Hermann Weyl? Well, as a young man he
too glimpsed Beauty, and the experience affected him for the rest of his
life.
I suppose I risk appearing to be the most blatant of intellectual snobs if
I admit that I see a parallel between Petrarch and Weyl. In his book of
self-revelation, "My Secret Book," Petrarch has a long and
intense imaginary dialog with St Augustine over Petrarch’s sufferings
as an errant human being who, though he has seen the truth and glory of
God, cannot get the idyllic but still very fleshly memory of Laura de Noves
out of his head. It is a wonderful and profound dialog, comprising about
100 pages, in which Petrarch argues with Augustine that his love for Laura
is based in purest admiration of beauty, and that this love has been the
inspiration of all his noteworthy achievements in life.
I won’t go into it, but Augustine will have nothing to do with
Petrarch’s imaginings. “It cannot be denied that the most
beautiful things are often loved dishonorably,” says Augustine. But,
Petrarch replies, “Loving her has increased my love for God.”
In the end, Augustine wins out handedly, and Petrarch admits his folly. It
is an amazing debate, all the more remarkable because it was written in
1347, at the dawn of humanistic thought.
Similarly, Weyl glimpsed Beauty in 1918 in his theory of metrical gauge
invariance, and then struggled to maintain his love against a disbelieving
and chiding Einstein. In a series of written correspondences that stretched
from 1918 to 1921, Weyl and Einstein debated long and hard over
Weyl’s 1918 theory. Try as he would, Einstein could not get Weyl to
acknowledge the theory’s fatal flaw.
Weyl sent a proof of the first edition of his book
"Space-Time-Matter" to Einstein for review. Along with the proof
he boldly tells Einstein that he has “succeeded in deriving
electricity and gravitation from the same source.” While Einstein is
initially ecstatic, he spots the flaw, for which there is no cure, and
replies “Regrettably, the basic hypothesis of the theory seems
unacceptable to me [although] the depth and audacity of which must fill
every reader with admiration.” Weyl counters with “Even if this
theory is only in its infant stage, I feel convinced that it contains no
less truth than [your] Theory of Gravitation.” In his book, Weyl
rhapsodizes rather poetically:
“…One Light and Life of Truth comprehends itself in Phenomena.
Our ears have caught a few of the fundamental chords from that harmony of
the spheres of which Pythagoras and Kepler once dreamed.”
But Einstein holds firm. Weyl weakens a bit: “Your rejection of the
theory for me is weighty [Weyl is all too aware of Einstein’s
renowned insight and scientific wisdom] … But my own brain still
keeps believing in it.”
Like Petrarch and his flawed love for Laura, Weyl is at last forced to face
the fact that his gauge theory is also flawed and, like Petrarch again,
Weyl tries to fix it up by a rather unsound rationalization of what’s
real and unreal in spacetime. For a time this isolates him somewhat from
Einstein, Pauli and others who are all too aware that Weyl is grasping at
straws.
But finally, and happily, Weyl concedes to the fatherly and caring
Einstein. Like Petrarch, Weyl picks up his life and moves on, and in 1929
he discovers the true gauge invariance principle, which lies not in
generalized Riemannian geometry but in quantum mechanics – a profound
and lasting discovery that represents Weyl’s reward for having
recognized at last the real truth behind the Beauty he had glimpsed one day
in 1918.
I suppose it would be the acme of naivete to compare the chiding Einstein
with Augustine, but I think the basic idea holds up. But if you think
I’m nuts, then go read "My Secret Book" and
"Space-Time-Matter" and decide for yourself.
A Final
Word on Majorana --
Posted by wostraub on Friday, May 13
2005
In 1986 the German-born Italian
director Donatello Dubini released a film entitled "Das Verschwinden
des Ettore Majorana" (The Disappearance of Ettore Majorana), which
starred Jean Seberg. Well, Blockbuster Video didn't have this one as it
turns out, so I'm giving up.
If you premultiply a conjugated Dirac spinor with the purely imaginary
gamma matrix $\gamma^2$, you get a charge-conjugated Majorana spinor. If
this is set equal to the Dirac spinor, then the object describes fermions
that act as their own antiparticles (some physicists believe the Majorana
spinor provides an accurate description of massive neutrinos). Well, I
guess you could have learned this from anybody, but it's about all I have
on the guy. I guess the story about him jumping into the Tirrenian Sea in
1938 was the best part after all.
No doubt you're foaming at the mouth for more, but until I learn Italian
I'm going to have to pass on Mr. Majorana. If you come across the movie,
I'd appreciate an email.
More on
Ettore Majorana --
Posted by wostraub on Thursday, May
12 2005
Earlier I mentioned the
brief life of Ettore Majorana, the brilliant Italian theoretical physicist
who mysteriously disappeared while on a short boat trip in 1938.
Off and on, for perhaps two years now, I have begun to study supersymmetry
theory, only to fall flat on my face. The material is not that difficult;
Dirac and Weyl spinors move in and around the theory, so there's a feeling
of comforting familiarity. But the stuff gets so compounded and interwoven
with so many details that I always give up. Interspersed in this mess are
references to "Majorana spinors," which are very similar to Weyl
spinors, but even closer to the concept of neutrinos. I always figured Majorana
was just some inconsequential guy who happened to come across a neat kind
of spinor. Now I'm beginning to see how unappreciative and stupid I've
been.
Almost all of the biographical material I can find on Majorana has to be
translated from Italian websites, and the Google translations just aren't
very good. Here's what I found today:
Majorana was born in 1906 in Catania, Italy. He and his family moved to
Rome in 1923, where he studied engineering until 1928. He switched to
theoretical physics, obtaining a PhD in 1929 with a dissertation entitled
"Quantum Theory of Radioactive Nuclei." Many considered Majorana
to be brighter than Enrico Fermi, who worked with him.
Immediately prior to his disappearance on 25 March 1938, a note was found
in his handwriting that included the plea "Do not condemn me, for you
do not know how much I suffer." Colleagues noted that on occasion he
regretted the knowledge he had acquired regarding nuclear fission and the
possibility of making an atomic bomb. Since Majorana was not a sickly
person, or in debt, or even lovesick, it was assumed that he had committed
suicide by throwing himself into the sea. His mother did not buy this; she
never mourned, but awaited his return until the day she died.
A neat mystery! Why can't television produce a drama like this, instead of
the tripe it continues to air?
Who the
Hell Was Ettore Majorana? -- Posted by wostraub
on Wednesday, May 11 2005
I've been reading a fascinating
account of the life of the late Italian physicist, Ettore Majorana. A
colleague of the great Enrico Fermi, Majorana also worked on spinor theory
and came up with a type of spinor very similar to Weyl's. Majorana was one
of the first scientists to recognize the role of the neutron in nuclear
physics, especially nuclear fission.
At the age of 32, Majorana was appointed the Chair of Theoretical Physics
at the University of Palermo in 1938. However, he either took French leave,
committed suicide or was washed overboard on a boat trip prior to taking up
residence at the school. Since he was privy to the inner secrets of nuclear
fission, rumors abound to this day that he was abducted or killed by the
Nazis. His body was never found. There have been unsubstantiated reports
over the years of Majorana being sighted in Italy and in South America. If
he did bail, he did a good job of covering his tracks.
Fermi noted that Majorana was an exceptionally gifted physicist who was
also exceedingly eccentric and severely lacking in common sense. Majorana
was therefore just your typical scientist.
There's a biography on the guy that I'm trying to locate. If I find
anything interesting on him, I'll put it up.
Radioactive
Decay Rates -- Posted
by wostraub on Friday, May 6 2005
This will be my last word
on the creationism vs evolution issue, as my sanity depends on it.
A creationist friend of mine once asserted that radioactive carbon dating
is subject to error, because the rate of C-14 creation in the upper
atmosphere depends upon the rate of cosmic ray influx from the sun, which
is not constant in time.
She was RIGHT. The concentration of C-14 in Earth's atmosphere has varied
with time, so the rate of uptake of C-14 by living organisms has not been
constant. However, the variation has not been overly significant. That's
one of the reasons why organic samples dated by C-14 methods are qualified
with +/- figures. This means that a human bone dated by C-14 to be 33,500
years old plus or minus 1,500 years is really about that old. It does NOT
mean that the bone can be post-Diluvian (younger than about 4,000 years).
Live with it -- there are fossils that are undeniably human that predate
Noah and his ark by many tens of thousands of years.
Other creationists have used similar arguments regarding potassium-argon
dating, saying that the rate of radioactive decay of unstable isotopic
elements can vary with time.
These arguments are WRONG. The radioactive half-life of an unstable
elemental isotope is a fixed, unchanging constant. To argue otherwise is
akin to saying that the probability of a fair coin coming up heads after an
infinite number of trials is 25%, or that the value of the transcendental
number PI depends on the day of the week. Live with it -- when an
Archaeopteryx fossil is dated at 150 million years, it really is about that
old. It cannot be 4,000 years old. Noah did not stash a pair of
Archaeopteryx dino-birds on the ark.
To deny this is to deny reality. If you deny reality, you are either insane
or a Republican. The difference is not spacious.
The
Newtonian Moment, One More Time -- Posted by wostraub
on Friday, May 6 2005
In an earlier post I described
the New York Public Library's exhibit on Isaac Newton, "The Newtonian
Moment." It must have been popular, because it followed me home. The
exhibit is now on display at the Huntington Library in San Marino. Part I
of the exhibit, "All Was Light," is on display until June 12;
Part II, "The Making of Modern Culture," will open here on July
23. Admittance is $15, a little steep to see some six or seven displays of
Newtoniana, but then there's the rest of the Huntington Library itself,
which is a must if you're in town. I've been going there for 40 years, and
I never tire of the place.
Weyl's
Spin Connection --
Posted by wostraub on Wednesday, May
4 2005
In his 1929 paper on quantum
mechanical gauge invariance, Weyl derived the spin connection for Dirac
spinors in curved manifolds (roughly akin to the affine connection that is
used in general relativity). Because spinor transformations are limited to
the SU(2) symmetry (that is, they are neither scalars nor vectors), Weyl's
spin connection, to the best of my knowledge, is the only route we have to
analyze the behavior of spinors in spaces warped by gravitational fields.
In case you haven't noticed, I'm rather enamored of both Weyl's 1918 theory
and the basic concept of particle spin. Particle spin is just so damned
fascinating to me! Some time ago I read a book that examined the spin
connection in what is known as a "Weyl space," which is the
manifold that fell out of Weyl's 1918 effort. I noticed that the spin
connection could be described in two ways, depending upon one's preferences
for simplicity. Like Weyl, I keep looking for ways to get his $\phi_\mu$
field into things; being retired, it's a source of amusement to me. [Physics
is amusing?! Maybe I've got Alzheimer's.]
Anyway, on the menu to the left of this site I've got a very rough draft of
a write-up on this subject. I'll add to it and fix it up as time permits.
This has nothing to do
with Weyl or science, but I thought I'd toss it in --
My father, who would have been 100 years old in January (he died in 1981),
graduated from high school in 1924. After years of searching, I finally
acquired a copy of his high school yearbook (along with five others from
the 1920s).
I don't have many photos of my father in his youth, but here he is in the
Class of 1924, at age 19, looking dapper and sharp in what must have been a
newly-purchased suit, and with carefully combed hair. The biographical
highlight concludes with "He was of the Prime in Worth." Dad was
far better looking than me, and when the picture was snapped he must have
thought his prospects in life were boundless.
Mom graduated from the same school in 1932. Unlike Dad, she kept her
yearbook, which now sits right next to Wheeler's "Spacetime
Physics" on my bookcase -- a very odd juxtaposition, indeed.
Sprinkled around her and there in these yearbooks are photos of my parents
as undergrads and club members -- tiny, easily-overlooked glimpses of my
folks sitting and standing with their classmates, almost all of whom are
now certainly gone. Autographs and notes abound in these books, with most saying
things like "Have a wonderful life."
Here is Violet Beer, who wrote that she remembered Dad. "He played in
the symphony orchestra, didn't he?" Indeed he did, and his trumpet
sits out in my garage. If alive, she must be 100 herself now.
Here is my uncle, Dad's brother, who graduated in 1930 at the age of 22.
He's gone, too.
And here ISN'T my father's other brother, who must have spent more time
playing hooky than attending class. He's also gone.
Here's Robert Piggott, my father's best friend. Dad used to tell me about a
certain Edna Piggott when Mom wasn't around. I assume Edna was Bob's
sister, but her picture's not in any of the books. Two days before Dad
passed away, his mind went back to the past, and he mentioned these names
to me before he died. Why were they important to him?
Here's Thera Loomis, Mom's best friend at high school. Where is she today?
Or IS she today? (I know that she married a guy named Abbott, and their son
became a physics teacher.)
Looking over the notes the kids scribbled in these yearbooks, it's easy to
see that life was harder then, and graduation from high school was not a
slam dunk. Sickness, bad grades, excessive truancy, the need to work --
even death -- kept many of my parents' classmates from graduating. An example:
IN MEMORIAM
Lucille Bredeweg, Class of 1929
July 13, 1911 -- December 13, 1927
The memorial photo shows a beautiful 16 year old girl. Uncle Ivan must have
known her, and mourned for her.
And here's Mom as a junior in 1931 as a member of the "Alchemy
Club." I never knew she took chemistry, which was my undergraduate
major.
My mother was beautiful in her youth, and Dad was very handsome
(unfortunately, those genes didn't get handed down to me). They married in
1932, and the marriage ended when Dad died 49 years later.
One of my favorite poems is Buffalo Bill (ee cummings, I believe, so I'll
keep it lower case):
Buffalo Bill's defunct
who used to ride a watersmooth-silver stallion
and break onetwothreefourfive pigeons
justlikethat,
Jesus.
he was a handsome man, and what i want to know is,
how do you like your blue-eyed boy,
Mr Death?
My mother used to tell me not to put flowers on her grave, because they
wouldn't do her any good. And as I place flowers on my parents' graves, I
know she was right. May God save their souls.
Thoughts
on Drake's Formula --
Posted by wostraub on Monday, May 2
2005
Some time ago I read the
book "It Must Be Beautiful: Great Equations in Modern Science," a
collection of articles by noted scientists and edited by Graham Farmelo.
One of the chapters in the book deals with Drake's Equation.
Frank Drake was a 1950s radio astronomer who worked at the National Radio
Astronomy Observatory in West Virginia. One day it occurred to him that the
intensity of domestic, commercial and military radio and television
transmissions far exceeded those arising from natural processes in the Sun,
and he began to think about how these transmissions might be intercepted
and analyzed by extraterrestrial observers. Turning his thoughts around, he
considered the possibility that humans might be able to intercept similar
transmissions from other solar systems. By the 1950s, there were numerous
powerful radio telescopes in operation around the world that could be
pressed into service (at least part of the time) to look for such
transmissions. But where to look, and what was the probability of finding
them?
Drake addressed the problem by setting up a simple formula. First, he set R
equal to the average rate at which stars are formed in the universe that
are reasonably similar to Earth's Sun. He then let fp be the fraction of
star systems in the observable universe that have planets. He then let fh
be the fraction of fp that represents planets suitable for habitation.
Similarly, he let fl, fi, and fc represent the fractions of those planets
having life, intelligence and structured technological civilizations.
Lastly, Drake set L equal to the average lifetime enjoyed by any given
civilization. He then postulated that the creation rate N of observable,
extraterrestrial radio-transmitting civilizations could be expressed simply
as
N = R x fp x fh x fl x fi x fc x L
Of course, N cannot be identically zero because there is at least one such
civilization, which is that of Mankind on Earth.
Since Drake first proposed this empirical (and perhaps even meaningless)
formula, there has been no end of respectable scientists and crackpots
alike that have come up with numerical figures for the above fractions.
There has been no consensus on the fractions, but the number N has
generally ranged from unity to a billion.
If N = 1, then it is almost certainly hopeless that the transmission source
will ever be found. If a billion, then there is a chance, though a small
one, because the heavenly sphere is huge compared with the number and size
of our radiotelescopes.
Reflect for a minute on the possibility of finding such a source. Let's say
that one is confirmed in the Andromeda Galaxy, about 2.2 million lights
years from Earth. Let's further assume that the transmission is intended to
convey a message, and we determine with absolute certainty that the message
is "Hello there." What exactly would that mean to us?
I would argue that the message would be, for all intents and purposes,
meaningless. We would never be able to talk to the message senders, or
explore or analyze their world. All we'd be able to do is consider the
certainty that extraterrestrial life exists. Would this improve Mankind's
lot in any meaningful way? I doubt it. There might even be a tendency to
see life as cheap and common. We could then blow ourselves to atoms, or
destroy our environment, secure in the knowledge that life, somewhere,
would go on. This is not to say that there might be some social
disorientation created by the knowledge that someone else is "out
there." Religious leaders and social scientists alike would have to
sort out the consequences of such knowledge, but I really can't see things
going much further than that.
Now consider the very real possibility that terrestrial Mankind is the ONLY
civilization that Drake's formula pertains to. Assume for a minute that
Mankind is unique to the universe. Would this knowledge not make every man,
woman and child on the planet an infinitely precious thing? Would it not
make every species now facing extinction on the planet something to be
protected and celebrated? Would it not make war seem like the ultimate
insanity?
I personally believe that God did indeed pull off other acts of creation in
the universe, and maybe a sizeable percentage of them involve intelligent
life. But it simply does not matter, because we have to live out our lives
here. I don't oppose the Search for Extraterrestrial Intelligence (SETI),
because I believe that one of the things God wanted us to do was explore
the universe we live in. But I wouldn't waste too many of our
already-limited resources in the search.
As for UFOs and the like, consider this: We haven't found any intelligent
extraterrestrial radio messages yet (and we've been looking for 50 years),
so chances are the LGM (Little Green Men) are quite far away. If so, then
statistically speaking their own chances of finding us (never mind the
requirement that they'd need warp drive technology to come here) is much
worse than finding a particular grain of sand in all the beaches of the
world. And if the LGM have indeed arrived, why are they making their
presence so difficult to confirm? If you're the least bit scientific about
it, I think you'd have to conclude, as I have, that UFOs either do not
exist or they are human time travelers who do not want their presence
known. If time travel to the past is possible, future historians would
absolutely love to visit past Earth (I know I would!), but might have to face
unfortunate consequences if their presence or technology were discovered
(just imagine George W. Bush and his war machine with a time-travel device
-- yike!). As unlikely as this scenario is, it's vastly more believable to
me than LGM.
The Accidental
Scientist? -- Posted
by wostraub on Monday, May 2 2005
Tim Russert talked to New
York Times columnist and author Thomas L. Friedman on Meet the Press
yesterday. Friedman was there mainly to push his new book "The World
is Flat," which sounds a wake-up call to an America that seems to be
sleeping while the world undergoes radical globalization. I don't always
agree with what Friedman has to say, but the views he promoted on the show
are very close to my own.
Friedman's flat-world scenario really refers to the fact that new
technologies are allowing countries like India, China and Ireland to
compete with the United States on a playing field that is getting leveled
more and more to their advantage every day. He believes that America's
leadership in science and engineering has become eroded due to an attitude
of arrogant "entitlement." Meanwhile, other countries are
producing far more PhDs in technical fields, and they're showing signs of
leaving us in the dust. Up until perhaps 10 years ago, foreign students
came here to study science and engineering, but the enormous rise in the
quality of foreign universities (coupled with American travel restrictions
imposed due to 9/11) is keeping them in their own countries, which then get
the primary benefit of their efforts. As a result, Friedman is seeing an
steady and alarming erosion in America's ability to compete with foreign
markets in technological fields.
To get America back on track, Friedman recommends that we develop a
"Moon Shot" program similar to what JFK initiated in the early
1960s (I would prefer something more akin to another Manhattan Project, but
perhaps it's all just symantics). And Friedman believes that this program
should be focused on energy self-sufficiency -- kicking the oil addiction
once and for all (because Peak Oil is almost certainly going to happen),
and developing cost-effective alternative energy sources (including solar,
wind, and nuclear). He even went so far as to recommend that the President
impose a $4 per gallon price on gasoline, beginning in 18 months, with the
generated revenues going to finance the program. Friedman even told Russert
that if Americans want to drive Hum-Vees, they should go to Iraq, implying
that gas-guzzlers like Hummers have no economic or moral place in the
world. Right on, Tom!
Friedman sees global warming as a bigger threat to the world than
terrorism. I personally see the biggest threat to be waning energy supplies
and the increased militarism of countries to secure whatever oil resources
remain after Peak Oil kicks in. Many scientists believe that we will run
out of fossil fuels before global warming becomes an acute threat to the
planet.
Regardless of who's right, Friedman's plan is a giant step in the right
direction. Energy self-sufficiency would require an enormous investment in
scientific research and development. America is probably the only country
that has the financial capability of undertaking such a task, and it
consequently offers an ideal opportunity for America to retake the lead in
science and technology.
Where I disagree with Friendman lies my belief that we should not trust in
technology alone to fix our problems. If you've ever studied Lagrangians in
math and physics, you already know that Nature has cooked things up so that
conjugate variables like ENERGY-TIME are minimized. This means that humans
should make every effort to conserve resources and minimize waste. Also, we
should minimize the amount of energy we throw away into ENTROPY. This
simply means that it is far better to not make a mess (like an oil spill or
air pollution) than to make it and then clean it up. Speaking system-wise,
a cleaned-up mess is even worse than one that is left alone. Of course, all
this flies in the face of that great god, Capitalism, so our current
attitudes will necessarily have to be adjusted -- and quickly.
As Friedman implies, all of this will require a hell of a lot of scientific
education. My belief is that when people are adequately educated in science
and math, they see the way things really should be, and they make changes
in their lifestyle. Friedman's thinking is an example of this; his own
background is in Mediterranean studies, but he has gotten himself educated
in science to the point where he sees the truth about things. Science and
math will do that to you.
Lastly, Friedman expressed his hope that President George W. Bush will read
his book and show the one thing that Friedman claims has been missing in
America to date -- true LEADERSHIP.
Lots of luck, Tom.
Weyl
Articles -- Posted by
wostraub on Monday, April 25 2005
Norbert Straumann,
Professor of Theoretical Physics at the University of Zurich, kindly sent
me a German reprint of his paper "On the Origin of Weyl's Gauge
Theories." I've been looking all over for a copy of this article, as
it gives an especially clear overview of Weyl's 1929 paper on
quantum-mechanical gauge invariance. [If I can get permission, I'll
translate it and post it as a pdf document on this site.] The paper
includes a reproduction of the postcard that Einstein sent to Weyl
regarding Weyl's original 1918 gauge theory. After I've translated
Einstein's comments, I'll post a photo of the postcard along with the
translation on the menu to the left.
Straumann (with Lochlain O'Raifeartaigh) has also written a very readable
overview of early gauge theories, including the 5-dimensional Kaluza-Klein
theory. The article is available online at
When
Einstein Lived in Pasadena -- Posted by wostraub
on Monday, April 18 2005
KPAS (Cable 55 in Pasadena)
has got a great 45-minute video titled "When Einstein Lived in
Pasadena." It's shown frequently, but to date I've only seen about
half of it.
It includes a neat story about how Nobelist Robert Millikin (remember the
Millikan oil drop experiment in school?), Caltech's president in the 1920s
and 1930s, enticed Einstein and his wife Elsa to visit Pasadena. They made
three visits (all in December, I believe) in 1931, 1932 and 1933. During
Einstein's first visit, he lived at 707 S. Oakland Avenue in Pasadena. The
house is still there, looking very much today as it did then. It's a fairly
simple, unassuming house in a neighborhood of nice, well-maintained homes
built in the 1920s and 1930s.
I stopped by Caltech this morning, and thought I'd also swing by and take a
picture of the Einstein house. You can download it from the menu on the
left (the file is about 550KB, so I hope you have a decent Internet
connection).
Of course, Millikin's plan was to get Einstein to join the Caltech faculty,
and he nearly succeeded. But Einstein was lured away by Princeton's
Institute for Advanced Study. When Einstein left Germany for good in 1933,
that's where he went. He died there on April 18, 1955, exactly 50 years ago
today.
I used to have a next-door neighbor, Seth Baker (who sadly passed away four
years ago at the age of 92), who was a communications professor at USC. He had lived in Pasadena since the 1920s, and he
saw Einstein during one of his visits (I think it was 1931). Einstein gave
a speech at the opening of Pasadena Junior College's then-new telescope
facility, and Seth snapped his photo (which unfortunately got lost over the
years). Too bad.
I haven't inquired about it, but you may be able to get a copy of the
Einstein video from Caltech. The website (which has lots of other neat
stuff) can be found at
http://www.archives.caltech.edu
Darfur -- Posted by wostraub on Thursday, April 14 2005
I rarely agree with anything
that neocon Max Boot (Council on Foreign Relations) writes, but in today's
Los Angeles Times he has hit on something that should touch every American.
That something is the genocidal situation in Sudan's Darfur region.
Over the past two years, religious and ethnic differences in that country
have resulted in over 300,000 deaths and more than 2 million displaced
refugees, who literally have nowhere to run. But the worst of it is the
torture and rape of hundreds of thousands of people, including children.
The Sudanese government, which itself is complicit in the crimes of radical
Islamic militias, is otherwise helpless to stop the crimes against humanity
that are occurring every day.
Boot bemoans the apparent lack of American will in mounting any serious
humanitarian assistance (military or otherwise), noting that we are too
bogged down in Afghanistan and Iraq to be of any real help. But that does
not absolve us of our Christian responsibility to help out when a human
crisis of this magnitude arises.
There are numerous charitable groups who are sincerely trying to alleviate
the suffering in Sudan. One of the best, in my opinion, is Doctors Without
Borders (DWB), which is already providing a wide range of medical and
humanitarian services to the region. However, like many other such groups,
its resources have been overstretched by the Indonesian tsunami disaster.
You don't have to mortgage your house to help out; even a few dollars can
be put to good use -- whatever you can spare. This is a chance for
self-loathing liberals and hypocritical right-wingers alike to do something
right for a change! :)
DWB can be reached at:
Doctors Without Borders
www.doctorswithoutborders.org
1-888-392-0392 toll free
"Leave wringing of your hands: peace! Sit you down,
And let me wring your heart"
-- Hamlet
Fifty
Years After Einstein and Weyl -- Posted by wostraub
on Monday, April 11 2005
Believe it or not, I can just
barely remember Mrs. Webster, my Kindergarten teacher at Northview
Elementary School in Duarte, California, mentioning to her otherwise
oblivious little charges that Albert Einstein had just died. I remember
this only because she made a big deal about how smart the guy was and how
important it was to do well in school. I also remember that I didn't know
who the hell Albert Einstein was. Now, if it was Sheriff John or Bozo the
Clown that had died, I would have have really taken notice.
That was fifty years ago this week.
It's odd that I can remember stuff that happened to me thirty, forty and
even fifty years ago (or at least I THINK I remember), but I can't recall
what I did last week to save my soul. Chalk it up to advanced middle age.
Einstein died in Princeton on April 18, 1955. Weyl was to follow him in
death in December of that year. I certainly DON'T remember Mrs. Douglas (my first-grade teacher
at Northview) telling us that Hermann Weyl had passed away!
Weyl and
Vierbeins -- Posted
by wostraub on Saturday, April 9
2005
While reading Weyl's 1929
paper for what seems to be the umteenth time (there are still parts of it
that I find puzzling), I began to wonder if it was Weyl who came up with
the VIERBEIN (or TETRAD) concept. Because there are no finite-dimensional
representations of spinors in gravity, the only way of tying a flat-space
spinor field to the curved spaces of gravitation is through vierbeins. A
vierbein is just a quantity having a Lorentz (flat space) index (usually
denoted by a Latin letter like a,b,c...) and a general coordinate or tensor
index, which is denoted by a Greek letter. Vierbeins are also used to
express flat-space tensor quantities into curved-space forms.
The vierbein is written simply as $e^a_\mu$, although either index can be
up or down (or even juxtaposed with the other). We raise or lower Latin
indices with the flat-space metric $\eta_{ab}$, while the curved-space
metric tensor $g_{\mu\nu}(x)$ is used to raise and lower Greek indices. We
can therefore express the curved-space metric tensor using the vierbein
formalism with the Lorentz metric:
Spinors can be viewed as flat-space fields that inhabit local tangent
spaces. They transform in general-coordinate spaces like scalars, but in
Lorentz space they transform using a certain unitary 2X2 matrix (see my
write-up on Weyl spinors on the menu to the left). This matrix involves the
Dirac gamma matrices $\gamma^\a$, which also live in a flat Lorentz space.
To get a spinor representation in a curved manifold, we use the unitary
transformation matrix as usual but with the gamma matrices expressed in
curved-space form, $\gamma^\mu(x)$. This is where the vierbein comes into
the picture:
$\gamma^\mu(x) = e^\mu_a \gamma^a$
Weyl used this vierbein approach in his 1929 paper. What puzzles me is
whether Weyl was the first to do this. I know that a year earlier, Einstein
(and maybe also Wigner) had used vierbeins, but in a completely different
application.
I do believe that Weyl was the first to derive the connection term for the
covariant derivative of a Lorentz vector. Using this term, one can
calculate the total covariant derivative of a mixed Lorentz-coordinate
tensor quantity. However, the covariant derivative of the vierbein
vanishes. In Weyl's 1918 theory, the covariant derivative of the metric
tensor is not zero, and this would also require a non-vanishing derivative
for the vierbein as well. I wonder if Weyl ever considered what happens to
the vierbein when the metric tensor in (1) is rescaled via $g_{\mu\nu}
-> \exp(\pi(x)) g_{\mu\nu}$. Do the vierbeins get rescaled, or does the
flat metric $\eta_{\ab}$ eat the scale factor?
Had Weyl completely given up on his earlier theory by the time he wrote his
1929 paper? I don't think so, because gravity was still very much on Weyl's
mind at the time. Indeed, the title of the paper (Elektron und Gravitation)
would have likely been Elektron und Wellenmechanik if Weyl had completely
sworn off his earlier effort.
It seems a shame to me that God called Weyl home in 1955 at the relatively
young age of 70, because so much neat physics was to arise in the 15 years
that followed his passing. I've often wondered what role Weyl might have
played in the development of this new physics, because his gauge principle
lies at the root of so much of it.
"DEAD
WRONG" -- Posted
by wostraub on Thursday, March 31
2005
The cover letter of the now-released
report from the President's Commission on the Intelligence Capabilities of
the United States Regarding Weapons of Mass Destruction claims that the
government was "DEAD WRONG" in its findings and that the
intelligence information it dumped on the American people and the world was
either "WORTHLESS" or "MISLEADING."
Analysis of the 618-page report (and I will read every word of it) by the
world's press has only just begun, but many are already saying that 1,533
American servicemen and women died in vain in Iraq, while more than 100,000
Iraqi civilians (innocent men, women and children) died as "collateral
damage." As Defense Secretary Donald Rumsfeld has said, "Stuff
happens" in war.
I am outraged by this report, and every American should feel the same!
PRESIDENT GEORGE W. BUSH IS A WAR CRIMINAL, AND SHOULD BE TRIED FOR HIGH CRIMES AND MISDEMEANORS AGAINST THE AMERICAN PEOPLE AND FOR CRIMES AGAINST HUMANITY. His cohorts in evil,
CHENEY, RUMSFELD, RICE, POWELL, WOLFOWITZ, PERLE, FEITH and MYERS should
also stand trial for treason.
The accessories to these crimes, in my opinion, are the AMERICAN PEOPLE.
You and I stood by and let a half-dozen monsters take over this country,
suspend the rights of American citizens, authorize the seizure, imprisonment,
torture and murder of innocent people, all for political and corporate
power. In doing so, these people lied and lied and lied, and we let them.
And we call ourselves Christians! God forgive us!
In his recent book "The Sorrows of Empire," Chalmers Johnson
reluctantly and sadly admits that the only options available to the
American people to change the current administration are probably through
radical means. If nothing changes, America will become a fascist empire
that will enslave us all.
The Commission's report pulls at the curtain hiding the President and his
co-conspirators. What will it take to rip it away completely? Will we wake
up then, or will we go back to sleep? THIS IS OUR COUNTRY, DAMN IT!!
Post Script: Notice how closely the announcements of the death of Terri
Schiavo and the release of the above report followed upon one another. Is
it a coincidence? Today's TV news is devoted almost 100% to Schiavo's
death, while the WMD report has been consistently absent from the
airwaves. I see this as more evidence that our beloved leaders are relying
upon the American public's addiction to triviality as a means of avoiding
culpability in issues that really matter.
On
Bioethics and Related Matters -- Posted by wostraub
on Tuesday, March 22 2005
I apologize for the
following rambling, unstructured diatribe, but I have other things to do so
I'm making it quick.
The Op-Ed section of today's Los Angeles Times has several interesting
articles involving the interplay between science and religion. One is
"Why Science Can't Show Us God" by Margaret Wertheim, the author
of "Pythagoras' Trousers" (which I have not read), which won a
book prize funded by the John Templeton Foundation (see my previous entry).
Another article is by Jeremy Rifkin, the noted scientist-ethicist and
author of "The Biotech Century" (which I have read). A third
article is from Robert Scheer, the political gadfly and notable Bush
critic, whom I happen to admire a lot in spite of the fact that (or perhaps
because) he is consistently hated by rightwingers because he happens to
have a mind and the courage to speak out against the mind-numbing hypocrisy
of our times.
These articles jumped out at me because not long ago I read "The
Beginning of Wisdom: Reading Genesis" by Leon R. Kass, MD, PhD, who in
2001 was appointed by President George W. Bush to the Chair of the
President's Council on Bioethics. This 700-page book is fascinating; it
analyzes the first book of the Old Testament in almost excruciating detail,
and thus provides much insight into the mind of God at the beginning of
creation that I think many people (myself included) were never aware of.
For example, the order that God chose to create the sun and moon, light,
the Earth, and mankind reflects much profound subtlety, while God's
oft-repeated pronouncement "...and He saw that it was good" was
NOT made when he created Adam. Very interesting, deep, neat stuff.
However, Kass elects to minimize the importance of several things that
reveal the author's shortcomings, which I believe spring from his
conservatism. For example, when Cain is sent away following Abel's murder,
he goes to Nod where "he knew his wife." Where did the Land of
Nod come from, and more importantly, where did his wife come from? These
are not new questions, and have in fact been asked for many centuries, but
Kass brushes them off with a single footnote citing incest as the possible
answer. He also admonishes the reader to not think about these questions
too much, but instead says "That he [Cain] had a wife (and
descendants), not where she came from or who she was, is what we here need
to know." In view of the meticulousness with which Kass has developed
his arguments (after all, he has written 700 pages on the Book of Genesis
ALONE), these kinds of brush-offs are most annoying. The Cain story and
footnote appears on Page 144, and I was so annoyed at Kass' attitude at
this point that I almost stopped reading the book. It's almost as if Kass,
when faced with inconsistencies that he cannot explain within the context
of his own belief system, is saying "Let's not dwell on this, because
I don't want you to use your own mind. Just accept my dogma without
question."
While Kass does not address bioethics in his book at all, I feel that to
dismiss the possible early biology of humanity as inconvenient IS
unethical. God did not fix the time scale in Genesis (he did not create the
Sun until Day Four, so millions of years could have been involved), and in
my opinion it's very possible that Cain's wife was an advanced
australopithicine or other early human biped that was capable of mating
with Cain. But this view presupposes evolution, which to any red-stater is
a no-no. Kass states that "None of these biblical teachings needs to
be retracted because of the findings of evolution." If Kass can
acknowledge evolution in this manner, why can't he simply acknowledge that
evolution is just a tool God invented to ensure that his creation can adapt
to changing environmental conditions? The denial of evolution is, to me, a
sin against bioethics because it denies biological reality, and a sin
against God because evolution is his creation.
On a separate but related note, Scheer points out the hypocrisy of the Bush
sycophants in their rabid determination to save the "life" of a
brain-dead patient (Terri Schiavo) for purely political purposes, in spite
of the fact that Governor George W. Bush himself championed a Texas law
permitting spouses and significant others to OK the withholding of
extraordinary life-saving measures in just these kinds of cases. This is
most CERTAINLY a case of bioethics that has been perverted by politicians
for their own selfish ends. The state courts have already weighed the
Schiavo case to the nth degree, and declared that Terri should be allowed
her appointment with God (and I have prayed that her soul is saved). Bush
and his fellow maniacs would rather Terri spend another few decades in a
brainless, lifeless limbo to further their own despicable causes. And the
fact that Congress jumped in to vote on this SINGLE case tells me that our
Constitution is in deep, deep trouble.
Meanwhile, Rifkin chimes in to voice his opposition to genetic engineering.
He reminds us that researchers are trying to create hybrid creatures
("chimeras") using spliced human and animal DNA so that they'll have more human-like laboratory
animals to experiment with. And why would such research be tolerated? So
that pharmaceutical companies can make billions by developing new drugs
tested on creatures like "humanzees," a truly horrendous cross
between humans and our closest genetic relative, the chimpanzee. It seems
that America's bioethicism can be stretched without limit provided there's
money to be made for the CEOs and the shareholders. Here, I'm 100% behind
Rifkin and presumably even Mr. Bush. God created every living species to be
separate and distinct, and by literally monkeying around with this set-up
we risk disaster.
Last but not least is Wertheim's otherwise excellent article, although I
really don't agree with what she says. She states that "rational
inference can never substitute for personal experience of the divine,"
and claims that God should not be equated with the structure and function
of nature. I agree -- God is not nature. But this avoids the real issue,
which is whether science and religion complement one another or must be
kept separate. I believe Wertheim is a proponent of the latter. Any person
can justify anything by simply claiming that "I received a message
from God," which is absolutely not scientifically verifiable. I defy
anyone to take away one's right to believe they have received divine
instructions from God, but this simply cannot be proved. As it stands,
people like this are locked up, unless they're the President of the United
States.
What Wertheim does not address is the fact that God gave us superb
reasoning organs called brains. The capabilities of our minds far surpass
the need to simply acknowledge God and the wisdom behind his creation. I
believe God gave us the ability to think because he wanted to challenge us,
to wonder about the physical world and to figure out how he did it. This
included questioning where we came from, where we're going, and what our
purpose is in life. It even included wondering whether or not God exists.
Otherwise, he could given us minds like sheep -- then we wouldn't have
sinned, and we'd all spend our eternal ovine afterlives peacefully munching
grass. Wertheim seems to want to maintain the wall between religion and
science. That's why biology texts in red-state schools are being rewritten
to emphasize allegorical creation over evolution, and that's why when Bush
tells us that 2 plus 2 is 5, we'll unquestionably accept it as divine
revelation.
On a purely personal note, I confess that I was not able to accept the
existence of God until I studied science and math. Then God's existence
became a rational certainty to me. My belief in Jesus Christ and personal
salvation, on the other hand, is more faith-based, but even there I see a
sound scientific reason based on the constraints imposed by God's gift of
free will: Did God want man to have free will? Yes. Did he know that free
will would cause us to know evil (because we have to know both good and
evil to have a choice)? Yes. Therefore, if mankind was to be saved from
himself, God had to provide a Savior. Without free will, there would be no
need for Jesus, but then we'd all be incapable of intelligent thought.
The Sciavo case is way overblown, of course. The war in Iraq and a host of
other ills is far more important, and I suspect our government is just
using Schiavo as a screen to keep the sheep from looking behind the
curtains.
The apostle Paul admitted that he would rather be dead and be with Jesus Christ
than continue to live and be subjected to the world and its temptations. I
cannot speak for Terri Schiavo's parents, who must truly love their
daughter. But in this case I say let Terri be with God, and I believe any
compassionate Christian bioethicist would agree with this.
More About
Growth -- Posted by wostraub on Thursday, March 10 2005
I was a civil engineer
for many years, and one thing I did was try to predict water demand using population
growth rates. The idea was to extrapolate population levels using regional
economic and socio-demographic data, then assign a per capita water demand
(typically 150 gallons per day per person). Multiplying one by the other
gave us the total water demand. The only trick is to get the future
population right. Curve fitting is fun!
Well, there are two ways to look as this type of planning. One assumes that
the population growth will occur no matter what, so the water purveyors had
better be ready for it. But the other way says that there might be a
cause-and-effect issue involved -- by planning for growth, the growth
occurs because we made it possible. No civil engineer ever said to the
Mayor, "This is all the water we'll ever have available, and when
that's allocated, the city must stop growing." Civil engineers are a
lot like politicians -- they'd rather be employed than be out of work.
I forget who said that humans will always take a resource and use it up as
quickly as possible, regardless of how much was originally available. If
this causes a problem, they will form blue ribbon committees consisting of
experts to study the problem, then produce a lengthy report that no one
will read or take action on. It's just human nature.
Take the infrastructure issue, for example.
The American Society of Civil Engineers (of which I've been a member for 29
years) recently published a report on the state of America's infrastructure
(that's water systems, dams, treatment plants, roads, bridges, etc.), and I
sure as hell hope people read this one. It gave the country a grade of
"D" based on calculated estimates of infrastructure
deterioration, and added that it will take $1.6 trillion over the next five
years to fix it nationwide (the grade is slightly better than the
"D-" ASCE gave it in 2001). Unfortunately, repairing a bridge is
not as "sexy" as designing and constructing one -- after all,
that's what we engineers went to school for! In my opinion, the
infrastructure problem will persist because it is a reminder of the
problems associated with growth, and people just don't want to face it.
Well, eventually we will have to face these problems, and there's a tried
and true method that the government has historically resorted to, and
always will. It's this -- ignore the problem until you can't anymore (a
disaster, etc.), then raise taxes on the middle class to pay for a partial
fix. And believe me, with the Bush cartel in power today, the middle class
is gonna get slammed pretty hard this time around.
ASCE's a great organization that's trying to do the right thing, and you
can help by at least getting educated. If you want to see the
infrastructure report, go to their website at ASCE.
The Peak
Oil Issue -- Posted
by wostraub on Thursday, March 10
2005
Since retiring four years
ago, I've been following the Peak Oil issue with increasing interest and
concern. It began in 1999 after I spoke with Dr. Albert Bartlett of the
University of Colorado at Boulder, who is a vocal proponent of the issue
(and, alas, a Cassandra because the issue's being ignored by the vast
majority of humans). Since then I have read Dr. Kenneth Deffeye's book,
"Hubbert's Peak," and I don't know how many other articles that
have come out.
Dr. Bartlett is fond of quoting his Third Law of Experts, which is
"For every PhD there is an equal and opposite PhD." By this he
means that if an expert comes out for or against something, there is
another expert who will counter those claims. So I decided to look at the
data myself; there are several web sites that have summarized the data.
There is no question that oil production is following a Gaussian (or bell)
curve. The oil gusher that began modestly enough in Titusville,
Pennsylvania back in 1859 grew into millions of oil wells around the world,
and the production of oil grew exponentially. In spite of a few blips (the
North Sea oil discovery in the 1970s was a kind of unexpected gift), the
world's production rate does indeed look Gaussian. The production curve for
the United States fits a Gaussian curve almost perfectly (and it peaked in
1970, which is why we're importing most of our oil nowadays).
Unless you believe that the world is flat and infinitely two-dimensional,
the world's supply of oil is indeed finite and will be exhausted at some
point in the future. But this is not the real problem; the problem is that
when world oil production hits the peak of the Gaussian curve, production
can only go in one direction -- down. When that happens, there will be no
such thing as CHEAP OIL anymore, and then really bad things will start to
happen.
Imagine -- every now and then some politician suggests raising the gasoline
tax a few pennies a gallon to pay for some pet project, and he/she gets
crucified for it because opponents scream that it'll hurt people and
businesses. After Peak Oil kicks in, and it will at some point, the base
cost of gasoline might be $10/gallon. What will we do then? Who wrote the
law that says gasoline can never go higher than $2/gallon?
Another thing that Bartlett says is that one of the saddest facts about us
humans is our unwillingness to understand the EXPONENTIAL FUNCTION. This is
a mathematical function that describes the rate of growth or decay of
something. Growth can be good or bad -- nobody wants a malignant tumor to
grow, for example -- but so-called "good" growth can be bad, too.
My observation is that no one really seems to know what "good"
growth is. A small town with a population of, say, 10,000 people might be
desperate for growth, as it would attract more goods and services as well
as tax revenues to pay for the public works infrastructure needed to
sustain the citizens. After a period of growth, the town's citizens might
start to say "That's enough growth, things are just right now."
But that is never the case; growth continues whether people want it or not.
People are still flocking to Los Angeles, where growth has truly destroyed
the lifestyle that once existed in the 1930s and 40s. Now it's just smog,
hellish traffic congestion, and high taxes. This is not what folks wanted
for LA, but it happened anyway. I think most people believe there's an
"ideal" growth rate at which nothing bad ever happens.
There are currently several ads running on TV featuring Erik Estrada
hawking residential lots in Florida (and Arkansas, of all places). The ads
say that growth is explosive, with the Florida community expected to
increase its population by 33% by the year 2010, so come on down! Good
Lord, who would want to live in a place that's growing like that?! I
believe people tend to think of growth as they do their bank accounts;
nobody wants an annual rate of return of only 2%, they want more. This is
understandable -- everyone wants more money, more goods and services. But
we humans do not know how to stop growth when it's not wanted anymore.
Housing developers now say that "people have to have a place to
live," and go on building. Or they talk about "sustainable
growth," which is a lame excuse to keep on building because it sounds
as if some smart person has a plan that will fix everything. The term is
also an oxymoron. Growth is growth; something that grows at only 1% per
year doubles itself in about 69 years. A community experiencing 10% population
growth (a "nice" figure for bank accounts) will double in size in
only 7 years. Do you want your city to grow that fast? How would you like
your doctor to tell you that your cancerous tumor is growing only a few
percent per year?
Peak Oil, if true, will abruptly stop growth, and it will stop it all
around the world. Unfortunately, it has the very real potential to rapidly
create chaos and human suffering of the kind not seen since Noah's flood.
Oil has been described as the nearest thing to a free lunch. Its energy
density surpasses all other sources of cost-effective energy. We should
have been using it to develop a truly sustainable energy source, like
large-scale solar power or safe nuclear reactors, rather than burn it in
12-MPG automobiles. Forget fusion -- it will never happen in our lifetime,
and if it does its development will require an enormous amount of energy
just to get it built and distributed.
To me, the only solution now is to conserve like we never have before. But
conservation is anathema to growth, and as long as humans believe growth is
good, we're doomed. That's one reason why I drive a hybrid car. It's a drop
in the bucket, but I'm trying to do my share.
Bartlett has a wonderful term for the point in time that Peak Oil proponents
are talking about; it's called the "Dirac Delta Function in the
Darkness." Try to imagine the history of mankind over the past 10,000
years or so. A space visitor looking down on Earth at night during that
time would see mostly darkness, because until Titusville came along there
were only scattered campfires and the like to serve us and keep us warm.
Then, a brilliant flash of light for maybe 150 years or so, representing
the Oil Age. After that, darkness again. The Dirac function, which
represents a sudden and intense "spike" of activity on the axis
representing time, is a very appropriate analogy.
I urge you to Google "peak oil" and look at some of the many
websites that address this issue. Politically, environmentally and
economically, it might very well be the defining issue of our age -- and
it's going to happen very quickly if it's true. A good site to check out is
www.fromthewilderness.com, which should open your eyes. You don't have to
believe everything you read, but at least get yourself educated so you can
decide for yourself.
Einstein
at the Skirball Museum
-- Posted by wostraub on Friday,
February 18 2005
Today my older son and I
visited the Einstein exhibit at the Skirball Museum in West LA. Lots of
neat stuff -- Einstein's grade school report card; Einstein's handwritten
reproduction of his 1905 special relativity theory; original letters to and
from many famous scientists and statesmen; his brass refractor telescope;
his magnetic compass; his smoking pipes and classical 78-rpm records; his
erroneous light-deflection calculation from 1912; and the "Holy
Geometry Book," an elementary text in German, given to Einstein as a
child by his uncle, which Einstein cherished as the source of his interest
in science and mathematics.
Also on display are letters to extra-marital paramours, of which he had
many, and the list of demands he handed to his estranged first wife,
Mileva, instructing her to silently deliver hot meals to his room and to
not expect any tokens of intimacy from him. This is Einstein, warts and
all.
To me, the best part of the exhibit focused on his later years, in which he
became increasingly involved with nuclear weapons control and human rights.
He was caught up only marginally in the McCarthy trials, but a paranoid
American government nevertheless considered Einstein to be a socialist
subversive. The FBI spied on him and compiled a 1,500-page file on his
activities. Reading some of these reports shows what a bunch of dangerous morons
Americans can be when they are frightened. That was 50 years ago and, alas,
it is happening in this country again.
Einstein lobbied strenuously for African Americans, whom he felt were being
disenfranchised of their civil and human rights. He was a friend of the
black actor Paul Robeson and the scholar-activist WEB Dubois. And when she was barred from staying at a
Princeton hotel following a performance in 1937, Einstein put the great
black soprano Marian Anderson up in his own house. Einstein defended
Robeson and Dubois against McCarthy, and noted that the only place they
were referred to as "niggers" was in their own country.
The exhibit is a testament to a great scientist who hated militarism and
anti-intellectualism. Einstein reluctantly urged FDR to move forward with
the Manhattan Project, but was devastated when the weapon was used on
Japanese civilians. Because of his pacifist and progressive beliefs, the
Daughters of the American Revolution wanted Einstein kicked out of America!
If he were alive today, I believe Einstein would be horrified and disgusted
by the current mad-dog militarism and pro-stupidity movement that is
prevalent in America now. May God save us!
The Einstein exhibit ends May 29, 2005. Admittance is only $12, and it's
well worth it, even if it has nothing on Hermann Weyl!
Beauty and
Truth -- Posted by wostraub on Thursday, February 17 2005
I died for Beauty - but
was scarce
Adjusted in the Tomb
When One who died for Truth, was lain
In an adjoining room -
He questioned softly "Why I failed"?
"For Beauty," I replied -
"And I - for Truth - Themself are One -
We Brethren are," He said -
And so, as Kinsmen, met a Night -
We talked between the Rooms -
Until the Moss had reached our lips -
And covered up - our names -
One of my favorite poets, Emily Dickinson wrote this poem in 1862, and I
have long wondered about its exact meaning. The above version represents
the way she actually wrote it, with those exasperating hyphens and a
tendency to capitalize words that apparently didn't need any emphasis. Her
poems are usually presented in a "cleaned up" format in modern
anthologies of her works, and are sometimes even almost rewritten.
The poem tells us that truth and beauty are the same thing, and that they
are worth dying for. But it also implies that they can fail -- Dickinson
depicts Truth and Beauty lying powerless in the grave. This bothers me a
great deal, because to me truth and beauty, at least from the scientific
and mathematical point of view, transcend the human experience. I doubt
very much if Ms Dickinson thought about it from that perspective.
The poem reminds me very much of the Old Testament, which describes our own
righteousness as filthy rags fit only for burning. It is mainly because of
this that I see Truth and Beauty in their noblest aspects as coming from
God, who is perfect. In a very real way, righteousness is truth and beauty
because it represents the way things really are according to God.
It is an unfortunate fact that many of today's premier scientists are
atheists or agnostics, and I have never been able to understand this.
Perhaps they see themselves as the creators of truth and beauty, rather
than the holders of minds that have been awakened by God. The book of
Ecclesiastes notes that wisdom is meaningless unless God is acknowledged as
its true author. I would go so far as to add that human wisdom is less than
meaningless -- quantum mechanics has given us a glimpse of God's mind, but
it has also been used by humans to build the most awful weapons imaginable.
And maybe this is what Dickinson was trying to tell us.
Beauty and
Symmetry -- Posted by
wostraub on Tuesday, February 8 2005
Needing a respite from
Zwiebach's string text, I read "Symmetry and the Beautiful
Universe," a new book by Leon Lederman and Christopher Hill. It
presents a very readable introduction to the various types of mathematical
symmetries that give rise to the physical laws we all know and love.
Although the book's authors mention the earth-shattering achievements of
Christina Aguilera, they more appropriately focus on the work of a far more
notable female, the mathematician Emmy Noether. Noether is the wunderfrau
whose 1918 theory revealed the deep connection between mathematical
symmetries (like gauge invariance) and conservation laws. The book offers a
substantive narration of Noether's life and work and is worth reading only
for this. The authors do not overlook the sad truth that the public is
almost totally ignorant of Noether's achievements as both the greatest
female mathematician who ever lived and the travails she bravely faced as a
Jewish intellectual at the dawn of the German hate machine in 1933.
Perhaps more importantly for a science book aimed at the general public,
the authors move past the usual grammar-school description of symmetry (oh
look, what a pretty snowflake!) and talk in relative depth about how
physical and mathematical symmetries lie at the core of our understanding
of matter and energy and their interactions.
I was disappointed that the book treats Hermann Weyl primarily as a
historical character who interacted with Noether, Einstein, Hilbert and
others. However, the authors appropriately put local gauge invariance
(Weyl's discovery) at the top of the symmetry list in terms of importance.
There's a nice description of the Higgs mechanism which, if proved (and it
will be, in my opinion), owes as much to Weyl as Peter Higgs himself.
Unfortunately, the authors neglected to summarize the symmetries and
conservation laws we're currently aware of. To the best of my knowledge,
they consist only of these: translational and rotational symmetry
(conservation of linear and angular momentum); time evolution and
translation (conservation of energy); time-reversal symmetry (conjugation
of charge); space reflection (conservation of parity); gauge symmetry
(conservation of electromagnetic and other types of charge); and permutation
symmetry (invariance of quantum statistics). There are several other
symmetries (like Lorentz invariance) and conservation laws (like
conservation of baryon and lepton number) that I am unable to place in
specific categories like the others. Gauge invariance was the last
continuous symmetry to be discovered, and that was in 1929. Are there any
others? Time will tell.
All of these symmetries and laws (either singly or in combination) are
absolutely inviolate. When fully understood and appreciated, they constitute
the best proof we have of the existence of a wise and benevolent God. When
we learn math and physics, we learn something about how God's mind works.
When we read the New Testament, we learn how to live from Jesus Christ. It
disturbs me greatly to know that my country is now being run by a bunch of
dangerous fools who understand neither science nor the philosophy of
Christ.
Weyl and
String Theory --
Posted by wostraub on Thursday,
January 27 2005
I'm nearing the end of
Zwiebach's book, and it has been rough going at times, but I'm beginning to
see what all the fuss is about. The theory is really quite beautiful (at
least the parts I understand), but some of the math is still very hard to
swallow. It remains to be seen if string theory is anything more than just
a pretty mathematical construct.
I was heartened to find that Weyl's gauge symmetry idea has found a place
in string theory as well. Like the rescaling of the metric tensor in
ordinary 4-space, a Weyl transformation in string theory comes about by
rescaling the Polyakov world-sheet metric $h_{\mu\nu}(\tau\rho)$ with an
arbitrary function of the surface parameters \tau and \rho. The Polyakov
action is invariant under such a transformation, so there must be a
conserved quantity associated with this symmetry (but I haven't read that
far yet). What would Weyl and Noether thought of all this?
I'm very grateful that Zwiebach put this book out. It's clearer than
anything else I've seen, and I highly recommend it as a self-study text.
Strings
Attached -- Posted by
wostraub on Wednesday, January 19
2005
I bought Barton
Zwiebach's book "A First Course in String Theory," and am about a
third of the way through. If you're anything like me (relatively
mathematically adept but a klutz nevertheless), you might want to invest in
this book, as it's just about the most readable text of its kind.
Almost all of the "Popular Science" kind of stuff that has been
written on string theory is a total waste of time -- golly-gee stuff that
is nothing more than handwaving and gushing about tiny vibrating strings in
multiple dimensions. However, the only other alternative is to actually do
the math, which can be excruciatingly difficult. Zwiebach's book was
intentionally written for people in between, and as far as I can seen he
has succeeded admirably.
Could the world really be a ten- or eleven-dimensional place connecting
multiple (or infinite) universes? Is this what Jesus meant when he said
"In my father's house are many mansions ... I go to prepare a place
for you"? The theory seems to be mathematically plausible, but there
also seems to be no way of actually demonstrating anything experimentally.
Our particle accelerators can now "see" down to about 10^(-18)
meter, but this is a long way from the so-called Planck scale of 10^(-35)
meter where those hidden extra dimensions may live.
At this time, string theory represents the only real candidate we have for
a unification of nature's fundamental forces. One of the brightest aspects
of the theory is that gravity falls out of it naturally (indeed, it is
actually necessary). The noted quantum physicist Michio Kaku has expressed
his hope that one day string theory (or its modern variant, M-theory) will
allow us to write down a single, inch-long equation that describes how the
physical world works in its entirety. If this happens, I will see it not
only as a fantastic intellectual achievement in its own right, but also as
the ultimate proof of an Intelligent Designer.
Just
Reminiscing -- Posted
by wostraub on Thursday, January 6
2005
Not long ago, I visited the
grave of Richard Feynman, Caltech physicist extraordinaire, who's planted
in the Mountain View Cemetery right next door to me in Altadena, California
(coincidentally, his grave's about a stone's throw from the house I was
born in). My parents moved here from Missouri in 1944, no doubt to take
advantage of the fantastic riveting and welding opportunities at Lockheed
during the war years. The house is still there, though a tad worse for
wear.
I mention this because my father would have been 100 years old on January
11 of this year, and I guess it's starting to get to me (I just turned 56
myself, so my own threescore and ten years are about 80% gone). In October
of last year, I visited the midwestern house my father was born in, the
streets I had played in during annual boyhood visits, and other sights and
stuff. Earlier, I mentioned my viewing of Newton's death mask in New York.
So, maybe I'm just feeling a little more mortal than usual.
On the return flight from New York, I stopped over in Missouri to do some
genealogical wandering. My parents and relatives are all from the
northeastern and southwestern parts of the state, and it took me some time
to find all the cemeteries they're buried in. I found them all, but seeing
their moss-covered headstones (some of them go back to the late 1700s) was
yet another reminder of my mortality. To make matters worse, it rained
constantly during my visit, and I was often ankle-deep in mud. It reminded
me of the joke in the PBS Civil War series about Tullahoma, Tennessee --
"Tulla" is an Indian word meaning "mud," while
"Homa" means "more mud."
But there's good news, too. A side trip to a little German
tavern/restaurant in Springfield, Illinois brought my attention to a brew
called Straub's Beer, which was served with the meal. I don't drink beer as
a rule, but this was an earned exception. Anyway, it turns out that
Straub's operates a regional brewery in St. Mary's, Pennsylvania, and it
was founded by a guy named Peter Straub from Baden-Wuerttemberg, Germany.
Well, that's where my Dad's family is from! As I can trace my father's
family there back to the 1400s, I have resolved that I will visit that area
this year (though I will try to stay away from the cemeteries). Now,
wouldn't it be neat if I found that Weyl had lived there at one time ...
Newton's
Face -- Posted by wostraub on Wednesday, January 5 2005
I stopped by the New York
Public Library recently, which is exhibiting a small but neat collection of
original publications and memoirs by Isaac Newton. "The Newtonian
Moment" includes three copies of Newton's Principia and numerous
scientific notebooks, some of which have handwritten comments and
pre-publication editorial corrections by the man himself. One describes an
experiment he conducted in which he thrust a metal probe along the side of
his eyeball; he noted that it produced some interesting optical effects!
The exhibit included what appeared to be one of the three original plaster
death masks taken of Newton within hours of his passing in 1727. I could
not get over how small and delicate the man's features were. He was elderly
when he died, but he still looked remarkably like the paintings I've seen
of him as a younger man. The mask faithfully captured facial artifacts like
pockmarks, scars and other defects that he had accumulated during his 84
years on earth.
Looking on Newton's face reminded me that no matter how great one's
achievements may be, things always end up this way. Newton, a devout Christian
whose prodigious religious writings far eclipsed his extensive scientific
output, would likely be amused by all this!
This excellent exhibit ends on February 5, 2005.
The
Conformal Tensor and Weyl's Gauge Theory -- Posted by wostraub on Tuesday, December 19 2006
Some time ago I wrote
about Weyl’s conformal tensor. It has some neat properties, but it
usually crops up only in a gravitation/cosmology context, and hardly ever
in differential geometry. But it was in that sense that the conformal
tensor was used by Einstein to get around his primary objection to
Weyl’s 1918 gauge theory, which was that the line element ds
is not invariant with respect to a metric gauge transformation (also known
as a conformal transformation of the metric).
Recall that an infinitesimal local gauge transformation of the metric gμν
→ (1 + ε π) gμν regauges the
lengths or magnitudes of vectors under physical transport, where π(x)
is the gauge parameter. Consequently, the line element ds2
= gμν dxμdxν is
also regauged in accordance with ds → ½ ε π ds.
Einstein’s argument was that ds can represent time as well
as distance, so time-independent processes such as the spacings of atomic
spectral lines can be invariant only if the line element is gauge
invariant. Since it is not, Einstein thought Weyl’s theory had to
be wrong.
But later, Einstein took up the problem once more. He felt that ds
could be made gauge invariant if the line element were revised to ds2
= J(x) gμν dxμdxν,
where J is a scalar function of the coordinates whose gauge
variation goes like δ J = -ε π J (that is, J
must be of gauge weight -1). This would cancel out the gauge change in
the metric tensor and leave the line element invariant.
Try as he could, Einstein could not come up with an appropriate scalar.
Finally, he noticed that the Weyl conformal tensor Cαμνβ
was exactly what he needed, for the combination √ Cαμνβ
Cαμνβ is of gauge weight -1 in a
Riemannian space.
Unfortunately, the Weyl conformal tensor vanishes in the absence of a
gravitational source, leaving a null line element (ds = 0) whose
gauge invariance is now trivial. Furthermore, the counterpart of the
foregoing expression in a Weyl space is unknown.
What Einstein apparently overlooked is the scale factor from the Weyl
theory itself, which considerably simplifies things. Consider the
integral quantity k ∫ φμ dxμ,
where k is a constant and φμ is
the Weyl vector (which he identified as the electromagnetic
four-potential). Under a metric gauge transformation, the Weyl vector
varies in accordance with δ φμ = λ
ε ∂μπ, where λ is
another constant. Gauge-transforming the above integral puts the gradient
∂μπ under the integral, which is
easily integrated. We can now set the Weyl scale factor to J via
J = ek ∫ φμ dxμ,
which, by appropriate selection of the constant k, will have
gauge weight -1.
This seems like a better approach than that provided by the conformal
tensor, because in the absence of the electromagnetic potential φμ
the exponential term is identically 1. Thus, the line element can be made
gauge invariant only in a Weyl space containing a non-zero
electromagnetic field!
I haven’t found any evidence that Weyl resorted to this
counterargument to Einstein’s objection, but by that time Weyl had
moved on, anyway. In 1929, Weyl applied the gauge concept to quantum
theory, which was a huge success. One has to assume that he never looked
back.
Hermann
Weyl and Dimensional Reduction -- Posted by wostraub
on Monday, December 18 2006
In his neat little book
The Dawning of Gauge Theory, Dublin physicist Lochlainn
O’Raifeartaigh writes
The procedure by which higher-dimensional
systems are reduced to lower-dimensional ones is called dimensional
reduction. The reason that dimensional reduction is so powerful from
the point of view of gauge theory is that it converts coordinate
transformations in the full space into gauge transformations in the
subspace.
Historically, the most
famous example of this statement comes from Kaluza-Klein theory. In 1919,
the German physicist Theodor Kaluza postulated the existence of a fifth
dimension which was hidden from observation because it was too small
to be seen. Kaluza thought that the electromagnetic four-potential of
Maxwell’s electrodynamics resided in this dimension, but that its
effects were observable only in the more familiar four-dimensional world
we humans reside in.
Kaluza assumed that the true metric tensor gμν(x)
was five-dimensional. Viewed as a 5x5 symmetric matrix, it has a 4x4
subblock representing ordinary four-dimensional spacetime, while the g0μ
"boundary" elements include the potential Aμ
by way of the identifications g0μ = g55Aμ
(μ = 0,1,2,3) and g55 is a constant. Thus, the
four-potential Aμ lives in the fifth dimension.
The potential is brought down into our world via dimensional reduction.
Kaluza took as his action quantity the integral
∫ √ –g R d5x
where the metric determinant g and the Ricci scalar R
are the old familiar ones, but now in five-dimensional form. Using
Kaluza’s above formulas for the g0μ
quantities, this five-dimensional integral can be reduced to
four-dimensional form, which is
∫ √ –g (R – FμνFμν
) d4x
This, amazingly, is the familiar expression for the combined
gravitational-electrodynamic action! (Physicist Ian Lawrie considers this
result a minor miracle. It isn't, because God just made it that way!) I
find it remarkable that Kaluza was able to deduce this way back in 1920,
because the calculation (while straightforward) is not trivial.
(Kaluza excitedly sent his paper to Einstein in 1919 to get a
recommendation for publication. Einstein, though quite impressed, was
nevertheless uncomfortable with a five-dimensional world, and so
suppressed publication until 1921. Kaluza was not particularly happy
about this!)
The Swedish physicist Oskar Klein published a subsequent paper in 1926
that made numerous important improvements to Kaluza’s idea in the
context of the then-emerging quantum theory. Hence the theory's present Kaluza-Klein
moniker.
Interestingly, in 1953 the great Austrian physicist Wolfgang Pauli took
Kaluza-Klein theory one step further -- that is, one dimension further,
to n = 6. This resulted in the very first non-abelian approach
to non-gravitational (particle) physics. Several years later, using a
similar approach, Yang and Mills developed the first consistent theory
for the strong interaction.
You might note that, in accordance with O’Raifeartaigh’s
assertion, the coordinate-invariant form of Kaluza’s
five-dimensional action results in a fully gauge-invariant term (√
-g FμνFμν) following
dimensional reduction, while the original action is not gauge invariant
at all. We got a gauge-invariant term by reducing the dimension by just
one; imagine the possibilities if one started with, say, an
eleven-dimensional action! This is the so-called M-theory of
string physics, which promises great things (but has delivered nothing to
date except beautiful mathematics). Note, however, that Kaluza-Klein
theory, while interesting, eventually lapsed into obscurity because it
did not predict any new observable phenomena – it was just a pretty
theory. String theory is now finding itself in the same boat, and if the
legions of brilliant physicists now grinding away (and maybe wasting
their precious talents) at this theory cannot produce anything predictive
from it (like explaining the magnitudes of the gravitational and
electromagnetic coupling constants), it may also be forgotten.
Did Hermann Weyl play around with dimensional reduction? Did he ever
consider the possibilities of a higher-dimensional gauge theory?
I’ve seen no evidence that he ever did. By dying in 1955, Weyl
missed Yang-Mills and a lot of other neat stuff he would have undoubtedly
contributed to.
Weyl was taken from us too soon.
Louise
Brooks: Lulu Forever
-- Posted by wostraub on Saturday,
December 16 2006
Peter Cowie's new book Louise
Brooks:Lulu Forever is out, and at long last. Finally we
have a large-format book with hundreds of rarely-seen photos,
motion-picture production stills and first-person accounts of 1920s
actress-flapper Louise Brooks, who would have turned 100 years old last
month (she passed away in 1985).
I probably would not care so much for this actress if it were not for the
fact that I first saw her signature film Pandora's Box (filmed
in Germany as Die Büchse der Pandora) as an impressionable young
college student in 1970. At the same time, I was taking an elective
course in literature (very odd for a chemistry major), where I was also
reading Vladimir Nabokov's irreducible masterpiece Lolita for
the first time. It was in Chapter 6 of the novel that I encountered
Monique, Professor Humbert's French girl-whore, the predecessor of one
Ms. Dolores Haze. To me, Louise and Monique were one and the same at the
time, and I have forgotten neither in all these years.
Of course, as a Christian I have mixed feelings about all this now, but
literature is literature, and life itself isn't squeaky clean. Humbert,
Monique and Lulu all paid dearly for their shortcomings (as did Louise
Brooks), and so I will let it go at that.
Cowie's book can be purchased from Amazon
for about $35. If you're interested, you might also consider buying Lolita*
which, in my humble opinion, is the third greatest book ever written
(right behind Hamlet and the New Testament). Exceedingly
well-written, hilarious, disturbing and heart-breaking at the same time,
it's all the more amazing that it was written by a Russian who picked up
the English language later in life (much like Joseph Conrad, who also
ranks right up there).
* Five points to the person who figures out the identity of
John Ray, Jr. PhD, credited as co-author of the book
Bombs
Bursting in Air --
Posted by wostraub on Tuesday,
December 12 2006
Several weeks ago, I
was driving through San Raphael near San Francisco and happened to stop
by Autodesk, the company founded by AutoCAD's creator, John Walker.
Coincidentally, Walker's name popped up on an Internet search with that
of John von Neumann, the great mathematical physicist
and close friend/colleague of Hermann Weyl (see my December 9 post). Von Neumann
worked on the Manhattan Project, where (among many other things) he
discovered that an atomic bomb would be much more destructive if
detonated high above the target area (something involving shock wave
pressures, which I know nothing about).
It turns out that John Walker is also interested in such things, if only
academically (unlike me, he is extremely wealthy and has even more time
on his hands). He has a website
that explains the effects of nuclear weapons on human populations,
something we should all get familiar with as long as President Bush is
running the world.
Anyway, Walker's site includes print-out materials and instructions for
making a nuclear effects calculator. It's basically a circular
slide rule that will allow you to ponder (in a very quantitative way) the
death and destruction that a nuclear device can have on your least
favorite city (Crawford, Texas, for example). Well, I made one, and it's
very neat. It's one way to personally experience the practical aspects of
the complicated science that folks like von Neumann, Oppenheimer and
Teller turned into godless, immoral sin.
[Note: Optimum burst height = maximum resultant death and
destruction]
Walker warns that his calculator won't be of much use in a post-nuclear
war world. But that may not be that far off -- I'll bet you anything that
one of the alternatives Mr. Bush is considering for the New Way Forwardİ
in Iraq is to nuke Iran, in which case all bets are off.
Weyl and
von Neumann --
Posted by wostraub on Saturday,
December 9 2006
From the recollections
of mathematician Herman Goldstine, friend of Hermann Weyl and the great
mathematical physicist John von Neumann, and (with von Neumann) one of
the developers of the early ENIAC computer:
Hermann Heine Goldstine, 1913-2004
"I always was
struck by the difference between Weyl and Johnny von Neumann. There are
jokes, one of which Johnny always swore was false. That's the story that,
I don't know, Hermann Weyl was going to prove some theorem, a very deep
and profound theorem, let's say it was the Riemann-Roch theorem. I don't
know if it was the Reimann-Roch theorem, but that was one I always have
trouble with, so let's say that was the theorem. And Weyl gave a lecture
on why this is a very deep, profound result, and he gave a very
complicated proof. And the apocryphal story goes that at the end of the
lecture there's this kid who is supposed to have raised his hand at the
back of the class and said, 'Professor Weyl, may I show you a proof?' And
goes up to the board and goes zip, zip, zip, zip, and in about 15 lines
has a brilliant proof of this thing.
"I asked Johnny about it, and he said no, that wasn't true. But it
is true, if you talk to Natasha Brunswick, who was in those days Natasha
Artin. Natasha says that there was always Johnny with these tight pants
on. All of Johnny's life, whatever size suit he bought, he always ate too
much, and the suit was always one size smaller than Johnny. Even as a
student in Göttingen, his behind was always ready to bulge out of his
pants. I guess Natasha and everybody in the class were always charmed.
"But Joachim, who was one of Hermann's children, told me that when
Hermann used to work in his house on Mercer Street, in the study in
there, you would hear groans coming out of the study. That Weyl worked at
things in sort of anguish, that it was hard for him, that he delivered
his theorems practically like a woman giving birth to a child. That's so
different from Johnny, because when he and I would be working at
something, when we'd get stuck, he'd say, 'Okay, that's it, ' and pack it
up. It might be that he'd phone at two in the morning to say, 'This is
how the proof goes.' But it might be three weeks, a month or so later, or
it might even be I who would come in a month or so later and say, 'This
is, maybe, how to go.' But he never struggled with something. When he got
stuck, he filed it somehow, and it just came out easily. I suspect that
Weyl was probably the deeper of the two mathematicians."
Louise
Brooks at 100 --
Posted by wostraub on Sunday,
December 3 2006
[Follow-up to my
October 17 post.] While visiting San Francisco recently, I stopped by the
city's Main Public Library, which is featuring an exhibit on the American
actress Louise Brooks. Brooks, who passed away in 1985, would have turned
100 on November 14.
Astonishingly beautiful, Brooks created the movies' "bobbed"
hairstyle look around 1926. I still remember the recollections of my late
mother who, as a lovely teenager herself in the late 1920s, begged and
begged her parents to get her hair bobbed á la Brooks. But as
strict Southern Baptists, such a hairstyle (not to mention even going to
the movies!) was absolutely verboten.
Back from SF, I was happy to have finally received Criterion
Collection's two-disc DVD set
of Brooks' early 1929 psycho-sexual drama Pandora's Box, the
actress' signature film (filmed in Berlin by the great German director,
Georg Wilhem Pabst). Regarded as one of the top ten greatest silent
movies of all time, Criterion's digitally remastered version of the
Munich Museum's restored film includes four different musical scores, Lulu
in Berlin (a rare filmed interview with the actress, produced in
1984), Looking for Lulu (the one-hour, 1998 Hugh Neeley
documentary on Brooks' life), the book Reflections on Pandora's Box,
and assorted essays, audio commentaries, interviews and stills. If you're
into this actress, this is a must-have DVD.
Brooks at age 64, in a rare 1971 interview with British filmmaker/
film essayist (and Harvard physics graduate!) Richard Leacock
Tragically, parental neglect and childhood sexual abuse (at the age of
nine) most likely destroyed Brooks' life, and she went on to become the
same kind of woman she portrayed in Pandora's Box and Diary
of a Lost Girl (also 1929). An ultra-liberal, chain-smoking,
alcoholic, partying sexual abandonee and iconoclastic loner until very
late in life, to her enduring credit she renewed her Catholic roots, took
up writing and turned herself around. She died of emphysema at the age of
78. May God save her soul.
My candle burns at
both ends; It will not last the night; But ah, my foes, and oh, my friends-- It gives a lovely light!
-- Edna St. Vincent Millay (1920)
Another
Hermann -- Posted
by wostraub on Monday, November 27
2006
If you’ve read my
articles on Weyl spinors, Dirac’s equation and quantum field theory
(or been bored by them), then you’ve probably wondered why no
mention was made of Grassmann numbers.
In QFT, scalar particles and fields can be described by a path integral
involving infinite-dimensional products (dφ1dφ2dφ3…dφinfinity
) under the integrals. But for fermions (electrons, quarks and the like),
whose fields are actually operators, the fields ψ(x) obey
instead an anticommuting algebra. Thus, ψ1ψ2
= - ψ2ψ1, which needless to say
complicates fermionic QFT. The first thing I thought when I saw this was
“well, matrices and differential operators can anticommute, so these
fields are just matrices or differentials.” No, I was wrong --
there are plain old ordinary numbers out there that can anticommute. They
are called Grassmann numbers.
Hermann Grassmann was born in Stettin, Germany in 1809. He loved math and
physics, but was also drawn to theology, chemistry, Latin, philosophy,
linguistics and neohumanism, so much so that he ultimately went on to
teach all of these subjects. Amazingly, he never took any formal classes
in mathematics or physics, yet he excelled in these subjects to the
extent that famous mathematicians of the day (including Möbius and
Kummer) considered him their equal. But because he was not formally
educated, Grassmann was not recognized in his day for his genius.
Grassmann was apparently the first researcher to realize that linear
vector spaces need not be limited to three dimensions. His work on
infinite-dimensional vector spaces predated by many years the work of Hermann
Weyl, Elie Cartan and other mathematicians, but intriguingly it also
provided the mathematical basis for fermionic QFT.
When Einstein tackled gravity in 1911, he found he needed a type of
mathematics that described gravitational physics that did not depend on
any particular coordinate system. He was advised by friends to study tensor
calculus, which had been worked out fifty years earlier by the likes
of Riemann, Christoffel and Ricci. I find it remarkable that quantum
electrodynamics would similarly be worked out in the 1940s using a
mathematics that had been discovered by Grassmann almost one hundred
years earlier.
The books I have on QFT explain only the merest fundamentals of Grassmann
algebra, while math books I have seen on the subject go far over my head.
Still, I am amazed that God could come up with something so strange and
counterintuitive -- and useful. In fact, since fermions make up all of
the ordinary matter in the universe (including you and me), God must have
had Grassmann numbers in mind from the very beginning. What a Creator!
One of the oddest things about Grassmann calculus is its underlying
simplicity. For example, the most complicated single-variable math
formula f(x) you can think of can be expanded as a Taylor
series, which in Grassmann algebra consists of just two terms: a + bx,
where a and b are constants. Thus, the basics of
Grassmann's discovery can be grasped by anyone in about five minutes.
You can read more about Hermann Grassmann here: Wikipedia
Units -- Posted by wostraub on Thursday, November 16
2006
One of the more
appealing aspects of Hermann Weyl's metrical gauge theory deals with the
concept of "units." Humans measure length in terms of meters
and feet and, in ancient times, cubits -- different, but all
interchangeable, and therefore the same thing. But in the presence of a
strong gravitational field (or when dealing with velocities approaching
the speed of light), the lengths of physical objects can become ambiguous
-- the length of a physical measuring rod, for example, can depend on the
observer.
In Weyl's original gauge theory, length can be continuously redefined as
one goes from one point in spacetime to another.
The basic units of length, time, mass etc. used to be based upon physical
objects or anthropological effects (all called "artifacts")
that were explicitly defined to represent the units they stood
for. For example, the meter used to be defined as 1/10,000,000 of the
distance from the equator to the North Pole (via Paris). Similarly, the
second was once defined as 1/86,400th of a day. In these examples, the
physical earth was a measurement artifact.
All of these artifact-based units (except the unit for mass) have since
been replaced by non-anthropological representations. For example, the
meter is now defined by a specified number of wavelengths of the emission
spectrum of a certain cesium isotope. Similarly, the speed of light in
vacuo is now fixed at exactly 299,729,458 meters per second. The
second itself has a specific definition based on isotopic transitions.
But to date the kilogram has resisted all such conversions. Officially,
it is still defined as the mass of this platinum-iridium alloy cylinder
having equal dimensions of length and diameter (39 mm) maintained near
Paris:
But this object is not entirely stable. It has been observed to change on
the order of 50 parts per billion per year (Corrosion? Sublimation? Old
age?). Now scientists are attempting to revise the definition of a
kilogram to a non-artifact basis. But it has been a difficult road.
The December issue of Scientific American describes the most
recent attempt. It is based on a nearly perfect, ultra-pure sphere of
crystalline silicon-28 having a number of atoms that is very nearly that
of Avogadro's number (roughly 6 x 1023), which is defined
itself as the number of anything in one mole of a pure elemental
substance.
But to my mind, this just replaces one artifact with another.
Furthermore, Avogadro's number is another "unit" having an
anthropological basis. Is there no way to define the unit of mass that is
free of some kind of human subjectivity?
Quantum physicists long ago realized that their equations could be
greatly simplified by setting Planck's constant and the speed of light to
unity. But this is really nothing more than a convenience, as these
simplifications only establish yet another set of units that is no better
than any other now in use.
My suggestion? Define the kilogram as the mass of one atom of hydrogen
and be done with it.
Weyl and
Einstein, Again --
Posted by wostraub on Friday,
November 10 2006
Taken aback by Hermann
Weyl's insistence that his gauge theory was valid despite the physical
evidence, Einstein wrote to his friend on 1 May 1918 with this remarkable
correspondence:
Could one really charge
the Lord with inconsequence for not seizing the opportunity you have
found to harmonize the physical world? I think not. If He had
made the world according to you, you see, Weyl II would have come along
to address Him reproachfully thus:
"Dear Lord, if it did not suit Thy way to give objective meaning to
the congruency of infinitesimal rigid bodies, so that when they are at a
distance from one another one cannot know whether or not they were
congruent, then why didst Thou, Inscrutable One, not decline to leave
this property to the angle or to the similarity? If two infinitely small,
initially congruent bodies K, K' are no longer able to be
brought into congruency after K' has made a round trip through
space, why should the similarity between K and K'
remain intact during this round trip? So it does not seem more natural
for the transformation of K' relative to K to be more general
than affine."
But because the Lord had already noticed, long before the development
of theoretical physics, that He cannot do justice to the opinions of
mankind, He simply does as He sees fit.
You may not always
agree with Einstein, but he just nails it here.
Stupid
Notation -- Posted
by wostraub on Friday, November 10
2006
From September 1918 until
late November of that year, Hermann Weyl and Einstein corresponded
repeatedly, with the main topic being Weyl's geometrical gauge theory.
Einstein loved the basic idea, but was upset over the fact that the line
element
in the theory was not gauge invariant. This unsettling little fact
ultimately doomed Weyl's idea.
But the two also bickered over Weyl's expression for the equation of the
geodesics, which is obtained by extremalizing the related integral
expression
.
Weyl's result was
where
Einstein vehemently stated that this was wrong. Weyl disagreed, and for
three months the issue came up again and again. The two men never
resolved it, and Weyl persisted in using his expression in all five
editions of his book Space-Time-matter. So who was correct?
Well, Einstein was right after all, but the whole thing was trivial, and
the two great scientists should have known better. The correct expression
is
What's the difference? It's in the partial derivative term for the metric
tensor: Weyl used a covariant term for x in the denominator when
he should have used the contravariant term.
It's no big deal, but it serves to show how important it is to maintain
consistency in your tensor notation. Few areas of mathematics have
displayed such a wide and bewildering range of notation as has tensor
calculus in its 150-year history. In the years immediately following
Einstein's general relativity theory, it seems that everyone was using a
different notation (even Einstein). Contravariant and covariant indices
were constantly being intermixed, and that is really what lies at the
bottom of this little Weyl-Einstein disagreement.
Spin and
the Early Universe
-- Posted by wostraub on Thursday,
October 19 2006
Abraham Loeb, Professor
of Astronomy at Harvard University, has an interesting article in the
November issue of Scientific American that deals with the
so-called "Dark Ages" of the universe.
According to current cosmological thought, about 380,000 years after the
Big Bang the universe had cooled enough for neutral (non-ionized)
hydrogen atoms to form. This prevented the microwave background radiation
from continuing to interact with electrons and ionized hydrogen via
Thomson scattering, so it began to leak out into the expanding universe.
Because stars had not yet started to form, there was no source of light,
and the universe went almost completely dark -- the start of the Dark
Ages.
During this darkness, which is believed to have lasted about a billion
years, gravitation gradually coalesced matter into stars and galaxies.
Light radiation from the resulting fusion reactions reionized most of the
hydrogen in the still-expanding universe, and light returned to the
cosmos.
As a consequence, the farthest astronomers can see with their telescopes
is about one billion light years. Whatever occurred prior to that cannot be
detected.
Or can it? Loeb believes that the universe preserves an imprint of the
Dark Ages through what he calls a menage a trois between the backround
radiation, the kinetic energy of neutral atoms, and a type of energy
called hydrogen spin energy. By modeling how these energies must have
interacted, astronomers can compare theoretical calculations with
observations of the sky at long radio wavelengths and test it out.
In the article, Loeb describes how a neutral hydrogen atom, consisting of
a proton and electron, can exist in its ground state in two distinct
energy states -- one with the spins of the proton and electron aligned,
and another in which the spins oppose each other. The energy difference
is minute, but becomes important when the background radiation level or
kinetic energy is smaller. Loeb believes that as the dark universe
expanded, the spin energy, radiation energy and kinetic energy took turns
being top dog, and that the echoes of this cosmic energy dance are still
detectable in the night sky.
If Loeb is right, then humans will be able to see the unseen, and perhaps
get an even better glimpse of the hand and mind of God.
Pandora's
Box on IFC -- Posted by wostraub on Tuesday, October 17 2006
Shot in Berlin in the
waning years of Germany's Weimar Republic, the late silent film classic,
"Pandora's Box" (Die Büchse der Pandora) is airing on
the Independent Film Channel (IFC) at midnight tonight and tomorrow at 7:45 am
PST (October 18). The film is shown uncut and uninterrupted, with both
its original German and English subtitles.
German filmmaker Georg Wilhelm Pabst's 1929 classic stars the hauntingly
beautiful American actress Louise Brooks (1906-85) as the libertine but
curiously innocent dancer/vamp Lulu. Now widely regarded as a cinematic
masterpiece, the film received surprisingly scathing reviews because of
its (then) shocking sexuality (but there's no nudity, parents).
Sickened by the excess and amorality of Hollywood (though hardly an
ingenue herself), and stuck in a series of profitable but brainless
"flapper" roles, Louise Brooks left to further her career in
Germany, where she starred as Lulu in "Pandora" and Thymiane in
"Diary of a Lost Girl" (Das Tagebuch einer Verlorenen,
also 1929). Following another starring role in the 1930 French film Prix
de Beauté ("Beauty Prize"), Brooks returned to the states.
She grudgingly made several more films in the 1930s, but she was
essentially blacklisted by the film industry because she refused to play
by its rules. She left Hollywood for good in 1939 and went to New York,
where she lived a rather impoverished, hand-to-mouth existence as best
she could until her death in 1985.
A victim of childhood sexual abuse and gross parental neglect, Brooks
ironically and tragically became a hedonistic abandonee herself, and by
the mid 1950s was, in her own words, "a questionable East Side
dame." But about that time she started writing about her life and
the many stars she had known personally (often very personally)
during her acting days. While her work was not prolific, her writing
demonstrates a remarkable talent for intelligent exposition. Her 1982
book, Lulu in Hollywood, reflects a truly brilliant mind.
A chronic drinker and smoker, Brooks succumbed to emphysema on August 8,
1985 after a long struggle with the disease.
Brooks led an absolutely amazing life, which is chronicled in Barry
Paris' excellent 1989 book, Louise Brooks: A Biography.
Silent film fans around the world will celebrate Louise's 100th birthday
next month (on November 14), at which time Criterion Collection Films
will release a digitally remastered DVD of Pandora with many extras, including a rare
filmed interview of the actress from 1979.
Melvin
Schwartz Dead at 73
-- Posted by wostraub on
Wednesday, August 30 2006
1988 Nobel Prize winner
Melvin Schwartz has died at 73. He shared the prize with Leon Lederman (The
God Particle) and Jack Steinberger for their work on the weak
interaction and their discovery that neutrinos come in different flavors.
But what appealed most to me about Schwartz was his approach to
electromagnetism.
Like many other befuddled graduate students in the 1970s, I had the great
misfortune of being forced to learn electrodynamics from J. Jackson's Classical
Electrodynamics, arguably the most difficult text on the subject
(the third edition was presumably "dumbed down" in the 1990s in
belated response). It's a shame that Schwartz' Principles of
Electrodynamics, first published in 1972, didn't achieve the same
(inexplicable) popularity as Jackson's book, because Schwartz' approach
is much clearer. It's even entertaining -- he starts it off with the
statement Electrodynamic theory is beautiful! What a wonderful
way to start a book!
Schwartz was one of the few physicists who insisted that electric and
magnetic fields, which are essentially the same thing, share the same
units. This in itself represents a tremendous simplication of the
subject, as the "units problem" in electrodynamics has caused
no end of troubles for students.
He similarly simplifies the understanding and calculation of the
Lienard-Wiechert potentials, another chronic stumbling block for mediocre
students like myself. The subject is laid bare in a wonderful chapter
entitled Let There Be Light!, in which the author unashamedly
shares his enthusiam for and appreciation of God's scientific and
mathematical wisdom. Indeed, Schwartz' writing style is peppered with
statements like At this point when the laws were being written, God
had to make a decision ... God naturally chose the antisymmetric tensor
as His medium of expression (Chapter 3). I love it!
Fortunately, Schwartz' book is available as a Dover
reprint and can be had for about $10, so you have no excuse for
not buying it. No physics library should be without it.
Dark
Matter Discovered?
-- Posted by wostraub on Tuesday,
August 22 2006
On August 15, a group
of astrophysicists announced they had seen indirect evidence for the
existence of dark matter. What does this mean?
For decades, astronomers have noticed that the rate of rotation of
galaxies does not jive with the amount of matter contained in them
– that is, there is not enough gravity contained in the galaxies to
keep them from flying apart. Astronomers therefore believe that there
must be a form of matter unlike normal matter that keeps the galaxies
together. This matter have been given the name dark matter. It
is optically invisible because it does not interact with ordinary matter.
Scientists have no idea what dark matter is composed of. Since it cannot
be made of ordinary stuff like protons and electrons, other, more exotic
forms of matter have been proposed (axions, anyons, etc.). But to date,
all this conjecturing has been purely theoretical.
Now a team of scientists (including members from the Stanford Linear
Accelerator Center and the University of Arizona) have announced indirect
evidence of dark matter in the Bullet Cluster, two groups of
over one thousand small galaxies that collided about 100 million years
ago in the constellation Carina, forming the shock wave shown in the
above photo (which is a composite of visible and x-ray photographs). As
the galaxies collided, the ordinary matter slowed down as one would
expect in any physical collision. However, the dark matter component,
which is immune to any kind of physical (mainly electromagnetic)
interaction, kept right on going. The scientists were able to deduce this
by measuring the amount of gravitational lensing caused by the
dark matter on more distant galaxies seen in the photo's background (dark
matter may not interact directly with ordinary matter, but it can still
affect it gravitationally). Thus, a cosmic collision event can serve as a
means of "filtering out" dark matter from its ordinary
counterpart. Indeed, there is speculation that past events have generated
"dark matter galaxies," whose presence can only be deduced by
gravitational lensing effects.
[Interesting Question: Is intelligent dark matter "life"
possible, or does it require the usual quarks and leptons? Maybe God is
not quarkic/leptonic at all!]
Who cares, you might be tempted to say. But astrophysicists have
estimated that dark matter makes up about 25% of the total matter in the
universe, whereas ordinary matter accounts for only about 5%. The
remaining 70% is thought to consist of dark energy, a
hypothetical energy field (called quintessence by some
scientists) that permeates the entire universe. Thus, the visible
universe you and I know and love accounts for only 5% of physical
reality. This concept is truly mind-boggling.
Hermann Weyl and others postulated that what we today call dark energy is
nothing more than a mathematical artifact of Einstein’s general
theory of relativity called the cosmological constant (I tend to
agree, as "quintessence" sounds a tad like the old
"ether" idea of the early 1900s). The cosmological constant is
simply a term in Einstein’s gravitational field equations which,
depending on its sign, can either act with or against the usual
attractive force of gravity. Many scientists believe that a non-zero,
repulsive cosmological constant exists and is responsible for the
observed large-scale repulsion effect that is forcing the universe to
expand at ever-greater velocities. If true, the universe will eventually
expand at the speed of light, resulting in a rather bleak future for all
existence.
The relationship between dark matter and dark energy has not been
established. If the human race can keep from blowing itself up over petty
tribal conflicts (which I find highly doubtful), we may have a chance at
someday understanding the fantastic universe that God has made for us.
String
Theory Unraveling?
-- Posted by wostraub on Tuesday,
August 15 2006
The great Austrian physicist
Wolfgang Pauli once remarked "What God hath put asunder, let no man
join." He was referring to the seemingly-intractable problem of
unifying quantum theory with general relativity, two theories that work
just fine by themselves but which have, since Hermann Weyl's time,
resisted all attempts at unification. It's the one great open problem of
physics, and every physicist worth his salt worries about it.
Why bother with unification when the theories work fine on their own?
Because only through unification can we simplify our world and begin to
grasp the mind of God. Recall James Clerk Maxwell, who in the 1860s
discovered that the electric field and magnetic field are the exact same
thing. Instead of a hodgepodge of unconnected, complicated vector equations,
we have the four Maxwell equations expressing the unified electromagnetic
field (which, I might add, are among the most beautiful mathematical
expressions mankind has ever gotten its hands on).
The unification problem can be traced to the fact that the general theory
of relativity is not renormalizable (which means that infinite
probabilities invariably arise during the perturbation step), so efforts
to describe gravitation using a quantum-perturbative approach fail
miserably.
Thirty-odd years ago, string theory promised a way around this problem.
The theory's early developers noted that it demands the existence of a
massive, spin-two particle, and it was assumed that the as-yet undetected
graviton feld would fit the bill.
Initially, it looked good on paper. But the most advanced version of
string theory requires that spacetime consist of 11 dimensions (1 time
dimension and 10 spacial dimensions) and not the usual 4. In order to
demonstrate the existence of all these extra dimensions, physicists would
need access to energies that are many magnitudes beyond those currently
produced in the most powerful particle accelerators. Indeed, these
energies rival that of the Big Bang itself, making it almost a certainty
that string theory can never be tested.
The theory's critics insist that any untestable theory is unscientific,
and therefore has no place in science. Some have even gone so far as to
say that it is akin to religious faith. Anti-evolutionists (and
Republicans) might be crazy about this, but not physicists.
My personal problem with string theory is far simpler -- I just can't
follow the mathematics. Back when Einstein first announced his general
theory of relativity in November 1915, it was said that only a dozen
people in the world could understand it. That was simply not true --
relativity is pretty straightforward, and while the math at the time was
unfamiliar, it wasn't difficult at all. Same thing with Heisenberg's
matrix mechanics in 1925 -- physicists just weren't all that familiar with
matrices, which even today's middle school kids can understand. String
theory, by comparison, is nothing less than a convoluted maze of
unbelievably complicated mathematics that seems beautiful only to the
relatively few people who can work with it. And in their own words, even
they don't really understand what they're doing!
So now we get the August 21 issue of Time magazine, which has an
article entitled The Unraveling of String Theory. It reports
that two new books by respectable physicists (Lee Smolin and Peter Woit)
are heralding a renewed criticism of string theory that might just catch
on.
The criticism advances the now decades-long suspicion that string theory,
which provides absolutely no testable predictions, may be nothing but
mathematics after all. If this can somehow be demonstrated, it would
serve to free up the minds of some pretty smart people (like Ed Witten at
the Institute for Advanced Study at Princeton) who currently are
obsessively pursuing M-theory, which is the 11-dimensional version of
strings I mentioned earlier.
In my mind, it's entirely possible that God considered basing physical
reality on string theory, but gave it up because it gave even him
headaches -- and a theory with headaches lacks beauty, and God's way of
thinking always involves beauty. But if not strings, then what? Is there
no way to unify gravity with quantum mechanics? Was Pauli's admonition
correct after all?
If string theory bombs, then we're back to where Weyl, Einstein, Pauli
and many others were 80 and 90 years ago. To be sure, we know a lot more
than those folks did, but one thing remains the same -- our intellectual
curiosity is simply not matched by our intellectual ability.
Straumann
Again -- Posted by wostraub on Thursday, August 3 2006
Here's a new article
from Norbert Straumann (University of Zürich), which was the basis of a
talk he gave in 2005. Some new stuff on Hermann Weyl and early gauge
theory, along with some reflections on the gauge principle in quantum
electrodynamics.
Persistence -- Posted by wostraub on Monday, July 31 2006
Edison once said that
discovery is 1% inspiration and 99% perspiration. Einstein asserted that
persistence trumps intelligence. Weyl's efforts to bail out his 1918
metrical gauge theory certainly represents a classic example of
persistence in the face of withering criticism. Weyl persisted because he
believed he was in possession of the truth.
Recall that Mr Einstein rejected Hermann Weyl’s original gauge
theory on the basis that it did not preserve the invariance of the line
element ds under a gauge transformation. In spite of the
simplicity of Einstein’s argument, Weyl tied himself in knots
desperately looking for a way out. As far as I know, he tried three
escape routes.
One was to assume that the ds of measurement was not the same as
the mathematical ds. That is, what we measure as ds is
a true invariant, whereas the mathematical version is not. This almost
metaphysical option was quickly dismissed by Einstein, Pauli, Eddington
and others.
Weyl then moved on to a line element that replaced the metric tensor gμν
with the Ricci tensor Rμν, a quantity that
is a true gauge invariant in Weyl’s geometry. This was an
interesting dodge, but it too was thrown out.
Weyl’s last gasp was to make ds invariant by multiplying
the metric tensor with a scalar J(x) of gauge weight –1,
so that the line element now goes like ds2 = J gμν
dxμdxν. After considerable thought,
Weyl realized that the only reasonable J-quantity had to be the
square root of Cμναβ Cμναβ,
where the C-quantity is the Weyl conformal tensor (see my pdf article
on this tensor on the menu to the left). This time Einstein was
impressed, though to this day no one knows if Weyl’s J-quantity
has any relevance in physics.
It is straightforward, if rather tedious, to calculate the equations of
the geodesics associated with Weyl’s J-invariant. I did
the calculation many years ago, and found that they’re completely
nonsensical. I’m sure Weyl did the same calculation, and maybe
that’s when he finally tossed in the towel.
Riemannian
Vectors in a Weyl Space -- Posted by wostraub
on Sunday, July 16 2006
I've posted the final
write-up on Riemannian Vectors in a Weyl Space, which tries to
address a mathematical inconsistency in the original Weyl theory (and
which has nothing to do with the conformal aspects of the theory). Fixing
the inconsistency leads to simple derivations of the Klein-Gordon and
Dirac equations. I've also included lots of other junk as food for
thought.
In this paper I've tried to include all the reasons why I think Weyl was
really close to a unified theory of the combined
gravitational-electrodynamic field, but please believe me when I say I
have no illusions that this will ever be rigorously demonstrated --
certainly not by my overly-simplistic treatment. Feel free to criticize.
Houston,
We Have a Problem
-- Posted by wostraub on Saturday,
July 15 2006
The disturbing events in
the Middle East and the recent hoopla over the space shuttle mission made
me think about that old science fiction movie in which astronauts take
off for the moon or Mars or someplace only to learn that a world war has
destroyed earth's population (along with everything else) and they have
nothing to return to. I'm also reminded of the scene in Planet of the
Apes (the 1960s version, that is) in which one of the returning
astronauts plants a little American flag in the lifeless soil, while
Charleton Heston laughs hysterically.
Now that the shuttle missions have been reduced to meaningless
public-relations trips designed to see whether the ship's insulation is
still intact, I am again forced to unveil the true stupidity behind
America's "space travel" experience. Here it is:
1. The shuttle orbits at an altitude of about 210 miles. At that height,
the force of gravity is still more than 90% of what it is here on earth's
surface. It's just like an astronautic flea who "soars" above
the surface of an onion by jumping onto the nearest outer skin layer. The
astronauts are not in "outer space."
2. The weightlessness of the astronauts is induced solely by the orbital
centripetal force. If they increased the shuttle's speed by only 2.5%,
they could orbit the earth at a height of one foot.
3. Shuttle missions are incredibly boring. There's little for the
astronauts to do other than maintain their life-support equipment. All
meaningful on-board experiments have been done to death, including
observing how crystals grow and ants propagate in microgravity. In their
free time, the astronauts can look out and see the curvature of the
earth. That's about it.
4. Without the protection of earth's atmosphere, dangerous levels of
cosmic rays constantly permeate the shuttle and its inhabitants. Do you
recall the "flashes of light" reported by Armstrong, Aldrin and
Collins during their interplanetary trip on Apollo 11? Those flashes were
caused by "Z particles" (cosmic ions with atomic weight around
that of carbon) piercing the astronauts' corneas. Meanwhile, microgravity
induces rapid loss of bone density and muscle tone.
5. There are literally thousands of pieces of space junk now orbiting the
earth, from grain-size ejecta particles to car-sized failed satellites.
And it's all flying around at many thousands of miles per hour -- many
times faster than a speeding bullet. NASA mission planners have to keep
track of every known chunk to avoid a catastrophic collision with the
shuttle. One of these days they'll lose track of something, with
disastrous results. All it takes is a particle the size of a grain of
salt.
6. In spite of all the high-tech you see in the orbiter, its boosters and
the tracking equipment, the shuttle is really nothing more than a fancy
Chinese rocket utilizing 2,000-year-old chemical technology. Chlorine-
and nitrogen-containing pollutants spewed out from each launch measurably
impact the earth's biosphere (chlorine is about the worst thing you can
imagine for the ozone layer).
7. President Bush says we're going to Mars! The round trip will take
years, cost more than $100 billion, and if cosmic rays don't kill the
astronauts the boredom will drive them insane. But it's a trip Americans
may have to buy into whether they like it or not, as it's rumored that Mars
has weapons of mass destruction. We can't just stand here and wait to be
killed! They don't call it the Red Planet for nothing!
The real reason why Americans support the "space" program is
that they don't know a solar system from a galaxy, a mile from a
megaparsec. I constantly hear people say things like "Our brave
astronauts are out there among the stars and galaxies, blazing the trail
to discovery." No, they're 200 miles above your head, idiot. And if
I ever hear that poem again about "touching the face of God"
(in a nuclear-armed fighter jet, yet), I'll scream. And
"spin-offs"? Please, did we have to spend a trillion bucks for Tang
and freeze-dried ice cream?
All this nonsense, and for what? A trifling trillion dollars or so to
date, and counting! The real purpose of these missions today? That's a
national secret, but I can tell you that it involves looking down on you
and me and everyone else, and not looking out on this wonderful universe
God made for us.
My suggestion? Let's first get our planet in order, make our resources
and human, animal and plant life sustainable, find a way to deal with our
aggressions, then reach for the heavens. Wouldn't this please God more
than what we're doing now?
Weyl and
Dirac -- Posted by wostraub on Monday, June 26 2006
Someone asked me for a
copy of a 1973 paper by P.A.M. Dirac today. I got it out of the garage to
email, and read it again for the first time in years. In it, Dirac uses Weyl's
gauge theory in an attempt to explain why the gravitational constant G
should be decreasing with time. In the paper, Dirac reveals a fondness
(if that's the right word) for Weyl that I had missed earlier. He even
provides a counter-argument for Einstein's famous objection against
Weyl's theory.
But then he goes on to describe how a non-moving charged particle in a
Weyl field can be used to break charge symmetry while maintaining CPT symmetry. Dirac's argument is simple: a vector
associated with a particle in a Weyl field changes magnitude according to
dL = φμ L dxμ. If the
particle is at rest, vector length still changes with the flow of time
according to dL = φ0 L dx0, where φ0
is the Coulomb potential and dx0 = cdt. If the change
in length is positive with increasing time, then it must shrink with
decreasing time (and vice versa). Regardless of the convention you
choose, the change in length is effected by the sign of the particle's
charge. Thus, symmetry is broken between positive and negative charge.
It's so beautiful.
Dirac, who won the 1933 Nobel Prize in Physics at the age of 31, was once
asked if there was anyone who was so smart even he couldn't understand.
"Weyl" was Dirac's answer.
Hermann
Weyl Resources Online
-- Posted by wostraub on Sunday,
June 25 2006
Among the papers, books
and articles I have collected on Hermann Weyl are a number of
contributions made by the German mathematical historian Erhard Scholz of
the University of Wupperthal. Scholz has written extensively about Weyl's
mathematics (from a primarily historical perspective), although I find
his English difficult to follow for some reason. Nevertheless, his online
materials are well worth acquiring. Just Google "erhard scholz,
weyl" and you'll finds lots of stuff, mostly in pdf format.
You might also want to Google "john l. bell, weyl" (presumably
no relation to the John S. Bell of Bell's Theorem fame) regarding several
online papers he's written on Weyl and his philosophical leanings. I
really don't "get" philosophy, but it's worth checking out.
Another resource that I have not yet acquired is "Hermann Weyl --
Mathematics and Physics, 1900-1927," a 1991 Harvard University PhD
dissertation by Skuli Sigurdsson. I haven't found it on any of the online
dissertation libraries, so it's probably not out there. I suppose I'll
have to get it directly from Harvard for much more than I care to pay.
I'll let you know if I find it.
[God bless the Pasadena, California Library! It acquired a set of
Einstein's collected writings (German and English translations) after a
loan request I made several months ago. The collection includes many
references to Weyl and his gauge theory and is just plain fun to read.]
Albert, Mileva
and the Noble Engineering Profession -- Posted by wostraub
on Thursday, June 22 2006
I've been reading the
letters that Einstein and his first wife, Mileva, wrote to each other in
the period 1914-19. This was a period of increasing estrangement between
the two of them following their split-up around 1913, and the
correspondence ranges from cordial to angry.
The letters take on a decidedly monetary tone after 1916, when it became
apparent that Einstein would eventually win the Nobel Prize. Mileva was
constantly asking for money, and Einstein provided it, often grudgingly.
Indeed, the letters from 1916 to 1919 seem to be nothing but arguments
over money. But Mileva was hard up, unemployed, and looking after two
young children, while Einstein, not yet famous, was himself just getting
by. (Einstein got the Nobel in 1921, and all the prize money, as he
promised, went to Mileva. It amounted to 121,572 Swedish krona. Worth
roughly $20,000 back then, it's not much today, and it wasn't that much
even in 1921. Nowadays, the prize is about $1 million.)
Mileva seems to have used their two boys, Hans Albert and Eduard
(nicknamed "Tete"), as a means of coercing funds from her
estranged husband, but the real villain of the story is Einstein himself,
who was never really cut out to be a husband or father. In the letters,
Einstein frequently apologizes for having to cancel out on planned visits
and such, and he seems content to simply blow kisses at them while coolly
blowing off Mileva's demands for money.
Later in the decade, we see letters to and from Einstein and his
soon-to-be second wife, Elsa. It's almost disgusting to experience
Einstein's kissy-kissy attitude with Elsa in these correspondences,
especially when one knows that this marriage was also a colossal failure.
Mileva was no beauty queen, but I could never understand Einstein's
attraction to that pudding of a woman, Elsa.
Anyway, I got mildly ticked off when I read Einstein's letter to Mileva
dated November 9, 1918 (also Weyl's 33rd birthday!), in which he impuned
all us noble engineers:
I am glad that Hans
has an intense interest in something. On just what it is directed is less
important to me, even if it is engineering, by God!
The nerve of the guy!
PS: Einstein's insult to the engineering profession backfired on him.
Hans Albert Einstein went on to become a noted professor of civil
engineering at UC Berkeley. Ha!
PPS: The letter, sent by Einstein without a return
address, was opened and read by a Berlin government censor, who
threatened to withhold future deliveries unless the address was clearly
marked. Sounds very similar to what's going on in this country today.
Looking
for Lulu -- Posted
by wostraub on Tuesday, June 20
2006
The other night Turner Classic Movies reaired the 1999 documentary Looking
for Lulu, a great one-hour overview of the life and works of
American silent film actor Louise Brooks (1906-1985), whose character
Lulu in the 1928 German classic Die Büchse der Pandora
(Pandora's Box) is said to have enraptured Adolf Hitler long before
Marlene Dietrich or Eva Braun came along. I'll bet anything Hermann Weyl
and Albert Einstein for once agreed with Hitler on something (however,
Hitler subsequently denounced the film itself as "degenerate
art").
I saw the film years ago at the old Vagabond Theatre in Los Angeles and
fell head over heels for this lady, whom I consider to be easily the most
beautiful film actor of all time. But she wasn't just a pretty face --
she was a child prodigy, educated in classical literature from an early
age, and a gifted classical dancer with an equally brilliant mind. In her
early films she played a typical 1920s "flapper," but soon left
for Germany to seek more demanding roles. In Germany she was known as Schwarze
Sturzhelm (Black Helmet) because of her unusual coiffure.
Amazon
sells the documentary DVD for $90. I burned it on DVD from the TCM airing and will send it out for a nominal fee
if you're interested, provided I don't get inundated by hundreds of
requests. Drop me a line.
PS: Pandora's Box is currently unavailable in Region 1 (USA) DVD format, and Kino Video does not plan to release
it anytime in the near future. If you live in the UCLA area, you can
attend a free screening of the film at the Armand Hammer Museum at 8 pm
on July 7, 2006.
Update: The
Criterion Collection will release the digitally remastered Pandora's
Box on American region DVD on November 10, 2006. It will include four
different musical soundtracks, the Looking for Lulu documentary,
stills, an interview with Brooks, and other extras.
Feynman's
Wheels -- Posted by
wostraub on Tuesday, June 20 2006
While
purging files from my Powerbook today, I came across a couple of pictures
having to do with Caltech physicist Richard Feynman (I don't remember
where I got them, but they must be fairly old, as the guy died in 1988).
Anyway, here is his license plate (I would have gotten quanta
for my plate, but we can excuse Feynman for the bad spelling).
This next shot of Feynman's van is interesting because it was obviously
taken while parked at the Dorothy Chandler Pavilion in downtown Los
Angeles. How do I know that? Because the tiered building in the
background is the home of my old employer, the Department of Water & Power!
It doesn't show up very well, but Feynman's van is covered with paintings
of (appropriately enough) Feynman diagrams. I wonder which auto
detail shop in Pasadena did that (I might get something Weylian
for my Prius).
Today's Factoid: The DWP has a really neat engineering library on the
fifth floor, and I looked out from that vantage point one day many years
ago to see then-Mayor Tom Bradley standing with Queen Elizabeth in the
Pavilion right across the street. You don't see that every day!
Fourth
Order -- Posted by wostraub on Friday, June 9 2006
One of Einstein's
objections to Weyl's theory of the combined gravitational/electrodynamic
field was that Weyl's field equations were of fourth, not second, order
in the metric tensor gμν and its
derivatives. However, variation of the fourth-order Weyl action
with respect to the metric tensor for empty spacetime gives
where the subscripted bar and double bar notation indicates partial and
covariant differentiation, respectively. It is relatively easy to show
that this differential equation has a non-trivial solution only when the
Ricci scalar R is a non-zero constant; the second term then
vanishes, and R can be divided out of the remainder, leaving a
term of second order. The surviving term can be solved (it's almost the
same as Schwarzschild's solution), giving the familiar expressions for
the advance of Mercury's perihelion, the deflection of starlight, etc.,
provided R is taken as a small constant.
The great Austrian physicist Wolfgang Pauli was aware of this calculation
as far back as 1921 (when he was just a 21-year-old kid), and noted that
Weyl's theory was just as capable of explaining the perihelion shift and
light deflection as was Einstein's theory.
The Schwarzschild-like solution includes a small repulsion term
(proportional to R) that might have something to do with the
observed accelerated expansion of the universe. Numerous researchers have
linked this term to the cosmological constant.
It is also interesting that Weyl's theory gives an Einstein tensor with a
1/4 term (rather than 1/2). This makes it automatically traceless, a
desirable feature that Einstein himself searched for in vain. No wonder
Weyl thought he was really on to something!
Ray
Davis Dead at 91 --
Posted by wostraub on Saturday,
June 3 2006
Raymond Davis, the
Brookhaven/University of Pennsylvania physical chemist and 2002 Nobel
Laureate who devised accurate neutrino detection and counting methods,
has died at his Blue Point, New York home. He was 91.
Davis, whom I wrote about on this site a few months ago, showed
conclusively that the number of neutrinos (elementary particles first
anticipated by the work of Hermann Weyl) reaching Earth from the sun is
only one-third the number predicted by the standard solar model developed
by the late astrophysicist John Bahcall (and a close friend of Davis). It
was learned in the 1980s that the three types of neutrino can morph into
one another, so out of 100 solar neutrinos emitted by the sun, only
one-third will still be solar neutrinos by the time they reach Earth. In
an amazing case of theoretical/experimental jousting, both scientists
were proved to be right!
At the time of Davis' Nobel Prize in Physics, Bahcall said of his friend
Ray is not only an
extraordinary scientific person, but also an extraordinary human being.
Ray treats the janitor in the laboratory with the same friendliness and
respect that he does the most senior scientist. And for that, he is loved
by his colleagues.
Davis is survived by
his wife of 57 years, Anna.
Hermann
Weyl and Imaginary Length -- Posted by wostraub
on Saturday, June 3 2006
Mathematical
symmetries, like Hermann Weyl's gauge symmetry, are essentially
undetectable aspects of action Lagrangians. This is the essence of all
mathematical symmetries. For example, the electromagnetic four-potential Aμ
has no absolute value -- an arbitrary gradient can be added to it without
changing Maxwell's equations. Before the advent of the gauge revolution
in physics, it was thought that the four-potential therefore has no
intrinsic meaning, and that the electric and magnetic fields E(x)
and B(x) represent the only true reality. Nowadays we know
better; E(x) and B(x) are themselves composed of
various derivatives of Aμ which, though
"undetectable" in a real physical sense, is the true underlying
reality. To paraphrase Columbia University's Brian Greene, trying to
determine the absolute value of Aμ is tantamount
to trying to figure out if the number 9 is happy.
Those of you who studied complex analysis in school may recall the theory
of residues, which provides a means for evaluating certain improper
integrals by integrating around the singular pole in the Argand plane.
Probably the first problem you solved involved the "single
pole" integral
where z is a complex quantity and i is the imaginary
number (-1)1/2. It is interesting to note that
Einstein's objection to Weyl's gauge theory can be avoided by an appeal
to this pathetically simple equation if we identify z with the
(variable) length of a vector L under parallel transplantation
in a Weyl manifold. In fact, the German mathematical physicist Fritz
London used this equation in 1927 to derive the quantized radii of
orbital electrons for the Bohr atom in a Weyl space.
The only downside is that quantities such as vector length L and
the four-potential itself become essentially imaginary quantities in Weyl
spacetime. This observation has interesting consequences, and perhaps the
most profound consequence is that Weyl's theory has validity only in
quantum mechanics (where imaginary quantities are de rigeur),
not geometry. If you have followed this site at all, then you already
know that in 1929 Weyl successfully applied his gauge concept to quantum
theory, where it now represents one of the most profound ideas in all
modern physics.
But there are some researchers (and they keep emailing me!) who insist
that imaginary vector length is ok provided the square of the
length L2 always comes out real (reminiscent of the
probability interpretation of the square of the wave function Ψ2,
which is real). Well, I still don't know about all this, but I keep
thinking about it. If one always gets L2 when doing a
physical measurement, its complex or imaginary aspects are totally hidden
from us because we always just take the square root, thinking that it,
too, is real. For example, the square root of the real quantity |z|2
is not +/- z, but a +/- ib, where a and b
are real numbers.
I'm an idiot, it's true, but you have to admit it keeps one's mind off
the moronic (and criminal) antics of President Bush, whose mind (and
legitimacy as a human being) are pure imaginary but whose crimes are all
too tragically real.
Hermann
Weyl and Steve Martin
-- Posted by wostraub on Saturday,
June 3 2006
The comedian Steve
Martin, who was a philosophy major at California State University at Long
Beach (my undergraduate school!), once said that he learned just enough
philosophy there to screw him up for the rest of his life. I was luckier
than he was -- not only have I never taken a class in the subject, it
wouldn't have made any difference anyway, because I just don't get
philosophy at all.
Stanford University Professor of Philosophy Thomas Ryckman does get it
and, more importantly, one of his specialties is the relationship between
the development of general relativity and the state of German philosophy
in the early 20th century. He has written a book on the subject, The
Reign of Relativity, in which both Einstein and Weyl play
prominent roles. Einstein himself was an armchair philosopher, but Weyl
was much more active on the subject. He was an early adherent of the
great German philosopher Edmund Husserl, and in fact married one of
Husserl's students, Helene Joseph.
Both Weyl and his wife were not only good philosophers, they were gifted
linguists. In the preface to his seminal book The Classical Groups:
Their Invariants and Representations, Weyl tells us
The gods have imposed
upon my writing the yoke of a foreign tongue [English] that was not sung
at my cradle.
(Weyl wrote this in English,
not German, and it has always been one of my favorite quotes of his.)
Anyway, back to Ryckman, who in January 2001 gave a lecture at Berkeley
on the influence of Husserl on Weyl's gauge idea. I will not pretend that
I understand the philosophical part, as my brain is not really wired for
it (and it's not a chronic "senior moment" thing for me,
either; like pure math and mathematical logic, it just plain escapes me).
But Ryckman's talk did provide a pretty good introduction to Weyl's gauge
principle, and you just might understand the rest of it as well,
especially if you have ever studied transcendental phenomenology
or logical empiricism (whatever the hell they are).
Here is Ryckman's lecture in Microsoft Word format: Article
Absolute
Truth in an Age of Lies -- Posted by wostraub
on Tuesday, May 30 2006
In a letter to Einstein
dated 19 May 1918, Hermann Weyl asserted
As a mathematician, I must
absolutely insist that my geometry is the true, local geometry [reine
Nahegeometrie]; the fact that Riemann posited only the special case Fμ
ν = 0 has no substantive legitimacy other than a merely
historical one ... If in the end your views are correct concerning the
actual world, then I would regret having to accuse the dear Lord of a
mathematical inconsistency.
Einstein himself once
stated that if his theory of general relativity (gravitation) was not
correct, he would have pitied the Lord for having overlooked such a
beautiful idea. This is what sheer truth and beauty does to a person --
it is so compelling that it takes on almost divine qualities, even to
scientists who are otherwise devoid of any religious faith. In the purest
of examples, it is completely objective, overriding any issues of ego or
self-righteousness.
Another case in point: I am rereading The Physics of Immortality:
Modern Cosmology, God and the Resurrection of the Dead by the noted
astrophysicist Frank Tipler (he's the same guy who proved that an
infinitely-long rotating cylinder could be used as a time-travel device).
I am looking at it again only for the mathematics, which may or may not
be relevant to the author's central thesis -- that religion is actually a
branch of physics, and that we will all be resurrected to eternal life by
God when the universe reaches the so-called Omega Point some
umpteen zillion years from now. As a newly-minted PhD in 1976, Tipler was
a diehard atheist until he experienced an epiphany of sorts while playing
with Einstein's gravitational field equations.
Whether one completely agrees with Tipler or not is beside the question
(as a Christian, I do not, but the stuff's interesting nevertheless). The
main point is that mathematical and physical truth has a beauty to it
that transcends much of what one experiences in day-to-day living. Part
of that truth (at least for me) is the realization that God exists and
had a purpose for putting us here in the first place (either as Adam and
Eve or as a couple of enlightened Australopithecines). I'm not
always sure he did the right thing, considering the mess we've made of
the world, but that's another story.
Weyl's own Road to Damascus occurred in 1918, when the concept of gauge
symmetry sprang into his mind. Einstein's was in the period 1913-15, when
he realized that another symmetry -- spacetime invariance -- could be
used to develop a theory of gravity. Both men were absolutely convinced
that they were in possession of the truth, and it changed their lives forever.
I often ask myself what inspires or moves other people. Is it absolute
truth, or what they themselves believe to be the truth based on what
others have told them? How can we recognize absolute truth, and not be
fooled by others (or ourselves) that that truth is not in fact a lie? To
me, the only path is math and science, in combination with the teachings
of Jesus Christ, because these things cannot lie. But not everyone finds
math and science to be very interesting. Can truth be found in accounting,
economics, politics, American Idol or auto mechanics? Can truth
be found in the New Testament if mathematics and physics are ignored? The
answer is very clear to me, but who am I to impose my beliefs on others?
Gravitational
Lensing of a Quasar
-- Posted by wostraub on Thursday,
May 25 2006
This amazing
photograph, taken by the Hubble Space Telescope, shows a cluster of
galaxies (about 7 billion light-years distant) splitting the image of a
single very distant quasar (about 10 billion LY away) into no fewer than
five images (the bright bluish-white points of light near the photo's
center). The galaxies act as a gravitational lens that
imperfectly reproduces the quasar's image in a circular arc about the galactic
field of view.
The photo also shows distorted images of galaxies near those responsible
for the lensing. Quasars (quasi-stellar objects) are themselves
the cores of galactic-sized objects containing super-massive black holes.
The extreme luminosity of a quasar is powered by matter being accreted
into the hole; as it spirals in, friction from the accretion heats the
matter up to the point where intense x-ray and gamma radiation comes
pouring out. Quasars were originally a great mystery to astrophysicists
because their great luminosities didn't seem to agree with their extreme
distances.
Another example of God's miracle universe. Sadly, the Bush
Administration, in its hatred and fear of legitimate science, has cut
funding for the Hubble Space Telescope, whose orbit will eventually decay
until it burns up in Earth's atmosphere. On the plus side, the money
saved will be available to help fund new wars of aggression for oil and
other dwindling resources, but in the name of truth and justice and
liberty and Christian goodness. But hey, whaddya want, America --
buck-fifty gasoline or a geeky orbiting science project?
Reality
v. Formalism --
Posted by wostraub on Sunday, May
21 2006
In the preface to his
1917 book The Continuum, Hermann Weyl tells us
It is not the purpose
of this work to conceal the bedrock on which the house of analysis is
founded with a fake wooden structure of formalism -- a structure which
can fool the reader and, ultimately, the author himself into believing
that [formalism] is the true foundation. Rather, I shall show that
this house is, to a great extent, built on sand.
Weyl goes on to say
that the then-popular use of arithmetic and irrational number theory to
solve the problem of the continuum should be stamped
(sarcastically) with the title Pythagoras. Therein lies the seed
of Weyl's thesis: much of real analysis at the time was based on circular
logic; it was non-rigorous, and therefore corrupted by false or
meaningless formalism. In his book, Weyl set out to make things right.
Today we have a few people around who are brilliant in both modern
mathematics and physics; Witten, Penrose and Baez come immediately to
mind. But Weyl was the first of this kind to come upon the scene. Trained
initially as a mathematician, he immediately ventured out into physics,
where he made many profound and fundamental discoveries.
Weyl was not afraid to attack what he perceived as either unintentional
misrepresentation or outright lies. In his book he attempts to set
straight issues that at the time contradicted unquestioned mathematical
thinking that greats like Dedikind had established decades earlier. Later,
when Weyl proposed his theory of the combined
gravitational-electromagnetic field, he did not back down even when his
theory was questioned by the great Einstein. Weyl's persistence, which
was based on a firm conviction that what he had proposed was based in
absolute truth and beauty, paid off when he applied his theory to the
then-emerging field of quantum mechanics. Weyl's gauge principle stands
today as one of the most profound tenets of quantum physics.
Who today has the courage to go up against established authority? Today
we are told lie after lie by our political leaders, and we swallow every
one of them, hook, line and sinker. Who among us has the courage to tell
Bush and Company that they are liars and false prophets?
Weyl denounced Hitler, but had to flee his beloved Germany in 1933
because neither he nor all his brilliant contempories could stem the tide
of nationalistic insanity that was sweeping the country. Not long
afterward, magazines and posters were displayed with Einstein's photo and
Noch ungehängt! (not yet hanged) all over Germany. Not
surprisingly, Einstein too fled the country. A dedicated Nazi effort to
discredit the theories of special and general relativity soon had the
German people thinking they had been tricked into believing a lot of
intellectual hokum. Books were burned, ideas themselves were banned, and
the great edifice that was once Deutsche Mathematik und Physik
was destroyed in favor of ignorant, arrogant nationalism.
Sadly, this is America today. But the danger is heightened infinitely by
America's possession of 10,000 nuclear bombs, spy satellites that can
watch and record everything we do and say, a hatred of legitimate science
and truth, and a crazed, fanatical, nationalistic Christian millennialism
that wants desperately to hasten Armageddon through unilateral,
preemptive war.
It is ironic that today Weyl and Einstein would almost certainly be
forced to return to Germany to escape the fascist madness that has
overtaken our country.
This is "circular logic" of a most disturbing kind. God save us
all.
Einstein
-- Collected Papers
-- Posted by wostraub on Monday,
May 8 2006
I spent several hours at
Caltech today perusing its copy of the Collected Papers of Einstein
(writings and correspondence, nine volumes, with a few English
translation versions). I went there to copy Einstein's correspondence
with Hermann Weyl, only to realize that I already have most of it.
But I was unprepared for the sheer volume of Einstein's correspondence
with other notables of the time. Letters in those days (this was 90 years
ago) was the email of their time, and Einstein must have spent a fair
amount of his free time just writing letters.
Particularly interesting are the letters to Mileva (his ex-wife) and son
Hans Albert, all of which show varying degrees of the man's emotions,
including warmth, concern, impatience, intractitude, and even a little
hostility. Though he genuinely cared for his two sons (in 1903 he and
Mileva had an out-of-wedlock daughter, Liserl, who was given up for
adoption), Einstein was not a family man, and his boys must have suffered
for it. Hans went on to become a professor of civil engineering at
Berkeley (he developed the Einstein bed load function in
sedimentation theory), while Eduard had mental problems all his life and
died at an early age. The fate of little Liserl is a mystery.
The Collected Papers abounds with correspondence between Einstein
and hundreds of notable scientists, mathematicians, philosophers and
political scientists. It's well-organized and makes fascinating reading,
if you've got the time. It's also available for purchase, but each volume
runs around $100, which is far beyond my pocketbook.
As for Weyl, Einstein and my favorite mathematical physicist wrote to
each other dozens of times, discussing many different topics, including
Weyl's gauge theory and related/unrelated mathematics, gravitation
theory, philosophy, German politics, the war, and what kind of salaries
professors should be given. Weyl was also the frequent subject of
Einstein's correspondence with others. It very much takes you back to a
time when it appeared that Einstein's relativistic theories (and generalizations)
would eventually solve all the standing problems in physics (this was
before quantum theory, of course).
Wilczek
on Weyl -- Posted
by wostraub on Friday, April 28
2006
In October 2005, MIT's Frank
Wilczek, the winner of the 2004 Nobel Prize in Physics (for discovering
the principle of quark asymptotic freedom), wrote a nice tribute to
Hermann Weyl. Here
it is in .PDF format.
Einstein
v. Weyl -- Posted
by wostraub on Wednesday, April 26
2006
Partly as a means of
ridding my mind of the preposterously immoral state of this country and
the criminal actions of the Bush Administration, I'm writing a brief
synopsis of the argument that Einstein and Weyl had regarding Weyl's
early metric gauge theory.
Several people have written in, asking what was behind Einstein's
objection to the theory, was it valid, did they remain friends, etc.
Hardly the appropriate subject matter for the general public, but the
story itself is fairly interesting, and I hope I can do it justice. I'm
getting ready for a trip, but I'll try to have it up in the next few
days.
Derivation
of the Weyl Conformal Tensor -- Posted by wostraub
on Wednesday, April 12 2006
Some time ago I
mentioned the Weyl conformal tensor, which is fundamental to the
understanding of gravitational tidal effects. Whereas Einstein's equation
(which involves only the Ricci tensor and scalar) describes gravitational
compression and compaction of matter (volume reduction via gravitational
attraction), the Weyl tensor is responsible for the deformation of
matter, with the initial volume of matter remaining intact. For example,
if you ever happen to fall into a black hole, your body's volume will be
retained but you'll be increasingly squished sideways and elongated in
the direction of the hole. This rather unpleasant phenomenon, known to
black hole afficionados and the cognoscenti as spaghettification,
is due to the Weyl conformal tensor. Why God allows black holes to exist
is anybody's guess (maybe just because they're fascinating).
How did Weyl discover this tensor? I could never find out. He seems to have
simply written it down (he was that good).
Numerous people have asked me how the tensor can be derived. Since I've
never seen the derivation, I'd never done the calculation, at least until
now. It's much simpler than you might think.
Weyl and
the Question of Asymmetric Time -- Posted by wostraub
on Thursday, April 6 2006
What really interests
me is whether God had any choice in the creation of the world. -- Albert Einstein
In the early 1920s,
Hermann Weyl discovered a new tensor quantity (the Weyl conformal
tensor) which is basically the Riemann-Christoffel curvature tensor with
the contracted pieces (the Ricci tensor and scalar) removed. The
resulting tensor is conformal (angle preserving) as well as metric gauge
invariant. Weyl must have come across the tensor while investigating the
consequences of his 1918 gauge theory and its presumed (but wrong)
unification of gravitation and electrodynamics, but I have been unable to
confirm this.
The Weyl curvature tensor is zero for flat spacetime, but for curved
manifolds it is non-zero, even in the absence of matter. The tensor is
responsible for gravitational tidal effects, in which (say) a
spherical collection of particles is contorted into a prolate ellipsoidal
shape (although the tensor preserves the initial volume). In fact, Weyl
curvature is responsible for the tidal bulge in the Earth's oceans caused
by the moon's gravitational pull. By contrast, the Ricci curvature terms
deform matter by gravitational compression, and volume is not preserved.
In 1979, the British mathematical physicist Roger Penrose (also a gifted
science writer) announced the Weyl Curvature Hypothesis, which
essentially states that the Weyl tensor was precisely zero when the Big
Bang occurred and will become infinite if and when the controversial Big
Crunch occurs. On the basis of this hypothesis, Penrose believes that
time must be asymmetrical; that is, time proceeds from the Big Bang to
the Big Crunch in only one direction. This contradicts the CPT theorem, which basically states that physics is
also valid for reversed time (that is, all equations remain valid if we
replace t with -t ). The laws of physics
may be time direction-invariant, but on a universal scale this might not
be the case. Penrose believes that a consistent quantum-gravity theory
(assuming we ever come into possession of it) will demonstrate that the
direction of time is really only one-way.
Whether the universe will end in a Big Crunch is debatable (current data
indicate that the universe will continue expanding forever), but what is
certain is that much of the matter in the late universe will coalesce
into black holes. Spacetime curvature near the event horizon of a black
hole is highly Weylian, so even if Penrose is wrong the totality of Weyl
curvature in the late universe will undoubtedly be extremely high if not
infinite.
I've mentioned Penrose before. He has two excellent (and very readable)
books out: The Emperor's New Mind (Penguin Books, 1989) and The
Road to Reality -- A Complete Guide to the Laws of the Universe
(Knopf, 2004). The latter book is a life-altering text that should be
read by everyone who has even the slightest interest in physics, the
universe, and God's role in it all. Buy this book, read it carefully, and
then place it next to the Bible and Hamlet on your bookshelf;
you will then be able to call yourself an enlightened member of the human
race.
The Weyl Curvature Hypothesis provides a direction for time's arrow, and
is therefore intimately connected with the increase of entropy in the
universe (as demanded by the second law of thermodynamics). Indeed,
Stephen Hawking and others have proved mathematically that the surface
area of a black hole's event horizon is proportional to the hole's
entropy. Thus, in the late universe, the level of entropy contained in
black holes will be enormous. By comparison, the entropy of spacetime at
the time of the Big Bang was very low, if not exactly zero. Thus, the Big
Bang and Big Crunch are distinctly different events. This calls into
question the reality of a "cyclic universe," that is, one that
comes into existence and then recollapses over and over.
I think Weyl would have been pleased that his curvature tensor is today
profoundly associated with the fate of the universe and related unsolved
problems in modern physics.
Inflation
Theory Getting Dissed
-- Posted by wostraub on Sunday,
March 19 2006
After the Washington
Post's article on cosmic inflationary theory came out a few days ago (and
discussed by me below), a veritable raft of conservative idiots have come
out of the woodwork proclaiming that it's just nonsense:
I just hate it when the
media reports carefully vetted scientific data as fact and not as just
one of many valid points of view. I'm not asking for them to ignore the
opinions of these so-called scientists, but they really should report the
fact there's a lot of controversy about whether this kind of evidence is
valid. LIke, were you there, huh, Mr. Hotshot Washington Post? As if this
ludicrous nonsense - a marble blows up like a baloon [sic] to become the
entire universe in a trillionth of a second - is more plausible than
Genesis? Give me a break!
To be fair, it doesn't
help things when the WaPo reports that the "universe expanded from
the size of a marble to the expanse of the entire cosmos in a trillionth
of a second." This is just plain wrong, but I think conservatives
would have a problem with the article even if it had been reported
accurately.
Alan Guth's inflation theory says that about 10-35 seconds
after the Big Bang, the universe began to expand at an exponential rate.
This increased rate of expansion lasted until about 10-30
seconds after the Bang (a total duration of very nearly 10-30
seconds). During this expansion, the volume of the still-infant universe
increased by a factor of some 1050. Expand something the size
of a marble by that factor, and you get a marble the size of a globular
cluster -- big, but still quite tiny compared to the size of the universe
today.
But I think conservative young-Earth creationists still have problems
with this. To them, there was nothing until God created it a scant 5,000
years or so ago. Adam and Eve rode to work on dinosaurs (they actually
believe this), and all animals were herbivorous (even T. rex,
who needed those fangs and claws to get through the notoriously chewy
plants that grew back then). Then came the Fall of Mankind, when some
animals literally became evil and began to eat their more peaceful
cousins. What utter, puerile nonsense! "Where were you when the Big
Bang occurred?" seems to be their standard question to cosmologists
these days. Well, you creationists weren't around either -- so there,
idiots.
I think a good part of the problem can be traced to the use of terms like
"millionths of a millionth of a trillionth of a second." These
terms are almost meaningless when taken out of context. I recall when my
high school physics teacher told us about Planck's constant, which is
roughly 6 x 10-34 joule-sec. My first thought was "Hell,
that's practically NOTHING. Anything that small is really no different
from ZERO." But I couldn't have been more wrong! The problem seems
to be related to the fact that humans cannot imagine something as small
as a decimal point followed by 33 zeros and the number 6.
Similarly, many people have a hard time imagining even a trillionth of a
second, which is much larger. "How could anything happen in a
millionth of a millionth of a second?" they ask. Well, an unstable
particle that has an average lifetime of that long is what particle
physicists call a very long-lived particle. Most unstable particles exist
for much shorter periods. Some are around for only 10-20
seconds.
The 10-35 second following the Big Bang is on the same level
of smallness as Planck's constant. If you want, we can sit here and talk
about tiny numbers all day long -- how about 10-1000 seconds?
Me, I can't even begin to imagine such small numbers. And I'm stupid at
both ends -- I can't imagine what infinity looks like, either.
But I know they exist.
What do I believe? If anybody really gives a damn, I believe that at t
= 0, God said "Let's have a quantum fluctuation take place in this
boring, expanseless nothing of a universe and get something interesting
going." BANG. Later, he created creatures with wonderful minds that
could actually calculate what the early universe MIGHT have looked like.
And, for better or for worse, God also created creatures that did not
want to use their minds. These he called "Republicans,"
although in the early days they went by the names Pharisees and Sadducees.
Inflation
Theory Verified? --
Posted by wostraub on Friday,
March 17 2006
New data from the
Wilkinson Microwave Anisotropy Probe (WMAP), a satellite launched in
2001, has provided scientists "smoking gun" proof that the
so-called Inflationary Universe, first proposed by astrophysicist Alan
Guth in 1981, is correct.
The data provide much finer details of the distribution of the cosmic
microwave background (CMB),
which is an "echo" of the Big Bang. The CMB was first detected in 1965 as a uniform,
isotropic radiation representing a universal thermal background of about
2.73o Kelvin, or 2.73 degrees above absolute zero. [Note: the
"degree" label o for Kelvin temperatures is always
suppressed, so it's just 2.73 K.]
The microwave radiation "echo" actually occurred about 270,000
years after the Big Bang. Why is that? It's because prior to that, the
expanding ball of ionized plasma and intense radiation was so opaque
("thick") that light from within couldn't get out. At around t
= 270,000 years the fireball had cooled to the point where the plasma
became transparent, and THERE WAS LIGHT!
Later data and refinements showed that the background radiation is not
quite uniform, but "granular." This graininess was predicted by
Guth's theory, but proof of the theory had eluded scientists until now.
The figure below is WMAP's map of space showing cooler (blue) and hotter
(red) regions (the temperature gradients are truly small, on the order of
a fraction of a Kelvin). Numerous scientists have remarked that looking
at the map is akin to looking at the face of God.
The inflationary theory states that the Big Bang, which occurred very
nearly 13.7 billion years ago, began as a uniform expansion of spacetime
which then accelerated briefly (and by briefly, I mean on the order of 10-30
seconds). This brief expansion, now almost jokingly called the
"Inflationary Epoch," was due to fluctuations in what is believed
to have been the false vacuum of the early stages of the Big Bang.
Columbia University's Dr. Brian Greene, a renowned astrophysicist, has
called the findings "spectacular and "stunning," while Dr.
Michael Turner, assistant director for mathematics and physical sciences
at the National Science Foundation, called the data "absolutely
amazing."
Meanwhile, concerned Republicans are scrambling to figure out how the
universe could be 13.7 billion years old, when everybody knows that God
created it only 5,000 years ago. Earlier today, there were indications
that Senate Majority Leader Bill Frist would propose a bill that would
nullify the WMAP data and imprison, torture and execute the study's
research scientists as godless, freedom-hating terrorists. But President
George W. Bush, who subsequently inquired about the cosmic microwave
background himself, remarked "If that there kozmick microwave is a
new kind of meat cooker, then I'm all fer it."
The Fly
in the Cathedral --
Posted by wostraub on Wednesday,
March 15 2006
I just finished reading
Brian Cathcart's excellent 2004 bookThe Fly in the Cathedral (Farrar, Straus and Giroux,
publishers), which describes in detail the discoveries of Rutherford (the
atomic nucleus), Chadwick (the neutron), and Cockcroft and Walton
(induced atomic fission). The book's title refers to a comment made by
Rutherford, whose original atomic "plum pudding" model gave way
to the correct view of a tiny, lone nucleus sitting in the vast empty
space of the atom -- like a fly in a cathedral.
But the bulk of Cathcart's book is taken up by the story of John
Cockcroft and Ernest Walton, who in early 1932 bombarded lithium metal
with accelerated protons. It is an intriguing tale of frustration, dashed
hopes, personal tragedy, and ultimate victory. The scientists' apparatus,
Neanderthal by today's standards, continually broke down, adding months
to their efforts (and always overshadowed by lack of funds in those early
days of worldwide depression). But their efforts were repaid many times
over -- they ultimately found to their utter amazement and delight that
protons could split lithium-7 -- a stable element -- into two helium
atoms. The Cockcroft-Walton experiment was the very first experimental
observation of man-made atomic fission, the transmutation of one element
into another, the first splitting of the atom.
The experiment also offered the very first practical test of Einstein's E
= mc2 formula. The observed 8.5-MeV energy of each
product helium nucleus balanced the books with respect to the reactant
particle energies. Like Einstein had said in 1905, mass and energy are
truly equivalent! In recognition of their work, the Nobel Committee
awarded Cockcroft and Walton the 1951 Nobel Prize in Physics.
The book's decription of Cockcroft/Walton's discovery is nothing short of
heartwarming, but it also includes tragedy. At the time of their triumph,
both men lost infants to childhood disease, tragedies that nearly
destroyed the men and their wives in spite of their groundbreaking
discovery.
But Cathcart saves the best for last. Ernest and Frieda Walton had a
long, happy marriage, and they went on to have four more children who all
pursued careers in science (three in physics!) Meanwhile, John and
Elizabeth Cockcroft went on to have five more children -- a scientist, an
engineer, a priest, a nurse, and a teacher.
God be praised!
The
Anthropic Principle
-- Posted by wostraub on
Wednesday, March 15 2006
For a long time I've
been planning to put up an article on the Anthropic Principle, which
purports to offer some proof that an intelligent, omniscient entity
(let's call it God) really did engineer the universe for our benefit.
There's actually quite a bit of evidence that such a principle is
scientifically valid, but, until I get around to it, here's one of the
more convincing arguments.
The Big Bang, which occurred about 13.7 billion years ago, started out
basically as a super-hot plasma of quarks and leptons. But within 2
minutes this plasma had cooled sufficiently to allow for the formation of
protons and neutrons. Using Boltzmann's equation and the fact that
neutrons decay into protons, electrons and antineutrinos (the life of an
unbound neutron is about 15 minutes), it can be shown that the expanding
fireball at age 2 minutes was composed of about 75% protons and 25%
neutrons (with relatively minor concentrations of other stuff). Thus,
three-fourths of the universe consisted of hydrogen, the basic fuel of
star formation via nucleosynthesis.
Gravity gradually coalesced clouds of matter into spheres and compressed
them to the point where nuclear fusion began in their cores. Almost all
of this fusion involves the creation of helium nuclei from hydrogen. This
is the kind of fusion that mankind is now trying to duplicate for
long-term energy generation.
But after a few billion years, many stars burn up their supplies of
hydrogen. A star begins to cool, contracts further under gravity, and
then the core heats up again as a result of the increasing pressure. The
temperatures eventually get so high that the star's helium can fuse into
carbon, oxygen, neon and several other low-atomic weight elements. Some
of these stars eventually explode as novas and supernovas, and their
supplies of carbon, oxygen, hydrogen and other trace elements is what makes
up all living things. All living things on Earth owe their existence to
stardust flung out by ancient star explosions. Humans, for example, are
composed of about 20% carbon and 65% oxygen, a reflection of the
equilibrium battles in the sun involving these two elements.
During the helium-burning phase of a middle-aged star, there are three
primary reactions going on that affect the formation of carbon. One is
the triple-alpha reaction, in which three helium nuclei fuse to
form a carbon-12 nucleus. The carbon formed in this process, however, can
be scavenged by another process in which a helium nucleus fuses with a
carbon nucleus to form oxygen-16. At the same time, oxygen-16 can also be
scavenged by a helium nucleus, yielding neon-20. It turns out that the
rates of these competing reactions and the physical constants that
determine their equilibrium points are very finely tuned; if the excited
states of carbon-12 and neon-20 nuclei were only slightly different,
all middle-aged stars would evolve atmospheres that are either
oxygen-rich and carbon-poor or composed predominently of neon. The
physics of these processes, including a few minor ones that take place
simulaneously with those I've described, have been worked out by
astrophysicists over the years to a gnat's eyebrow. If the
fundamental physics of the elementary particles making up carbon, oxygen,
helium and neon were displaced by only a few parts per million, life
could not exist anywhere in the universe. Thus, the universe as we know
it must have been designed, or we wouldn't be here.
However, some physicists have argued that, if the many-worlds
interpretation of quantum physics is valid, then our universe is just one
of an infinite number of possible universes in which the physics happened
to be "just right." In the vast majority of these other
universes, the physics is "off" and life does not exist. In
this way of thinking, a designer God would not be necessary because life
exists here because of a statistical fluke.
But this argument is flawed. The processes I described above represent
only a single example of the Anthropic Principle. There are many other
processes that are also finely tuned for the existence of life, and the
totality of these processes makes the statistical argument really hard to
accept. I have estimated that, given the totality of
"life-favorable" physical processes and constants, on average
only one such universe would arise out of 1040 universes.
While I suppose this is still statistically possible, it seems much
easier just to admit the existence of God. In my mind, these numbers
imply that the non-existence of God is statistically about one
in 10-40. To me, that's essentially zero.
So get over it -- God exists! Whether he/she/it is Jehovah, Allah or Brahma
is purely a matter of faith. And I'll leave it at that for now.
Post Script -- Speaking of faith, where do a lot of Americans derive it?
I recall about a year and a half ago a grilled cheese sandwich that sold
on eBay for $28,000. Why? Because it had what appeared to be the figure
of Jesus Christ on it (the pan it was cooked in was subsequently
auctioned off for $20,000). Since then, I've heard of trees, pancakes,
highway overpass stains, and hotcross buns that appeared to depict
Christian figures. All of these events made a big splash in the media,
and literally thousands of people made pilgrimages to these
"holy" sites. Yet the average American knows nothing at all
about the scientific Anthropic Principle, which to me represents the only
rational way of looking at physical "proof" of God's presence.
Americans truly are idiots.
Saunders
MacLane and Mathematics Under the Nazis -- Posted by wostraub
on Sunday, March 12 2006
While researching some notes
on Hermann Weyl’s tenure at Göttingen during the period 1930-33, I
came across a story involving the American mathematician Saunders MacLane
of the University of Chicago. MacLane was a gifted 1930 Yale mathematics
graduate who wanted to further his studies by attending the best graduate
school in the world. This led him, in 1931, to the Mathematics Institute
at the University of Göttingen in Germany, which was then universally
regarded at the finest school of its kind. Its previous and then-current mathematics
instructors included the likes of Gauss, Riemann, Dirichlet, Klein,
Minkowski, Courant, Hilbert, Noether, and Weyl.
MacLane’s arrival at the university coincided with the turbulent
political, economic and social scenario that was plaguing Germany at the
time. It would shortly result in the demise of the Weimar Republic and
give rise to Adolf Hitler and the Nazi Party.
Hitler was appointed Chancellor of Germany on 30 January 1933. A month
later (27 February) the Reichstag (German parliament) building was set on
fire, supposedly by a member of the German Communist Party, but most
probably by a mentally ill transient (who was quickly executed).
Regardless of the real cause, the Nazis used the incident to foment the
fear that social and liberal radicals in the country wanted to overthrow
the government.
Their first step was to enact the "Reichstag Fire Decree" (Reichstagsbrandverordnung)
in March 1933, which nullified many of the key civil liberties of German
citizens set forth in the country’s constitution. With Nazis
already occupying prominent positions in the government, the decree was
used as a legal tool to suppress publications deemed unfriendly to the Nazi
Party. It also allowed the Nazis to imprison anyone considered to be in
opposition to their policies and actions. The decree is generally
considered to be the Nazis’ first major effort to establish a
dictatorial, one-party German state.
However, the Nazis feared that the Reichstag Fire Decree would be
insufficient to bring about total control of the country. Consequently,
on 23 March 1933 they engineered the Reichtag's passage of the
"Enabling Act" (Ermächtigungsgesetz). This act
provided the Nazis the means of establishing total dictatorial control by
legal mandate, because now Hitler and his Nazi-dominated cabinet could
enact laws without interference by (or even participation of) the
Reichstag.
The formal name of the Enabling Act was the "Law to Remedy the
Distress of the People and the Reich" (Gesetz zur Behebung der
Not von Volk und Reich). Cleverly worded as such, the German people
were quickly brought on board Hitler’s plan to protect them through
harsh (but seemingly benevolent) means.
The Nazis’ third step was to implement Article 48 of the Weimar
Constitution. In reaction to the instability that arose in Germany
immediately following its defeat in World War I, the government had
amended the constitution to provide for emergency powers that might be
needed to quell public unrest, insurgency, and the possibility of civil
war. Article 48 was implemented via the "Order of the Reich
President for the Protection of the People and the State" (Verordnung
des Reichspräsidenten zum Schutz von Volk und Staat). Under the
provisions of the article, Hitler and his cabinet acquired essentially
unlimited power in Germany, all done legally and within the constraints
of the constitution. This effectively ended the Weimar Republic. Germany,
now officially a dictatorship, thus inaugurated the Third Reich.
Now back to MacLane who, in early 1933, was working under the guidance of
Göttingen assistant professor Paul Bernays. He knew Weyl well, and on one
occasion attended a dance party that Weyl and his wife gave at their apartment.
Though the political strife made life uneasy, these were heady times for
the young MacLane, who regularly came into contact with the greats of
contemporary German mathematics. He even came into the presence of Hitler
and Hermann Göring at an opera, but acknowledged later that he failed at
the time to recognize the inherent evil in these men. MacLane later
thought about how he might have changed history if he'd carried a pistol
that night!
On 7 April 1933, following the country’s short but complete
takeover just a month earlier, all Jewish professors (along with everyone
not considered totally committed to the National Socialists) were
summarily fired. By month’s end Courant, Noether, Neugenbauer,
Bernstein, Bernays, Hertz and Lewy were drummed out of the university.
MacClane, forced to seek a new advisor, went to Weyl, who took him on.
MacClane subsequently received his doctorate in the summer of that year,
just prior to Weyl’s decision to leave the country as well (Weyl
was a Christian, but his wife had a Jewish background, so their two sons
were considered to be Jewish).
So, by the summer of 1933 the world-renowned Mathematics Institute of the
University of Göttingen had been decimated. A total of 18 professors had
been forced to leave. A similar fate befell other universities across the
country.
MacLane returned home with his wife, Dorothy, in August 1933. In his own
words, he had personally witnessed “the damage done to academic and
mathematical life by any subordination to populism, political pressure
and proposed political principles.”
MacLane ended up at the University of Chicago, where he received many
awards for his work in mathematics, especially algebraic logic. He died
in 2005 at the age of 95.
I bring up this little story because I see what I consider to be an
irrefutable parallel between what happened to Germany in 1933 with what
is happening in my own country today. By the latter part of 2001,
President George W. Bush, an unsuccessful, uncharismatic, witless,
incurious, unrecovered alcoholic, was well on his way to an inglorious
one-term presidency. In his first eight months in office he had
accomplished nothing of any importance, and his approval ratings were
well below those of his unpopular, one-term father, George Sr. Then came
September 11.
The Pentagon and Twin Towers attacks, like the Reichstag fire, breathed
new life into Bush’s foundering presidency. And like the Enabling
Act and the enactment of Article 48, the ridiculously-named "Patriot
Act" and the recently uncovered governmental domestic spying scandal
have given Bush and his zealots unprecented, almost dictatorial power.
And, like in Germany in 1933, the American people have bought into the
lies of the Bush Adminstration because they’ve been taught to be
afraid.
What we’ve seen from Bush since 9/11 is an unremitting horror of
illegal war, missing WMDs, legalized killing, torture, imprisonment,
secret back-alley meetings and deals to benefit the corporations,
environmental destruction, astronomical deficits, wiped-out surpluses,
degraded civil liberties, hatred of objective scientific inquiry,
mega-capitalism and materialism, and unbelievable religious hypocrisy.
The United States, thanks to Bush, is today almost univerally hated
around the world.
I’m going to make a prediction before I close this overly-long
diatribe: I predict that within a year we will hear about a new scandal
involving illegal Bush Administration spying on the election plans of the
Democratic Party. While Nixon couldn’t pull it off because what he
did was deemed illegal and immoral (even by Republicans), such niceties
simply do not carry weight any more under the Bush Reich.
May God save this country. Even so, come Lord Jesus.
PS - You can download a five-page PDF document of MacLane's personal
reminiscences of Göttingen at MacLane.pdf
"Ich
fahre nach Pasadena ..." -- Posted by wostraub
on Sunday, March 5 2006
Here's a brief letter (along with its English
translation) that Einstein wrote just prior to his second visit to
Pasadena in 1931. In it, he lauds America's love of science and its
ability to balance production and consumption.
How times have changed. Americans now prefer superstition, video games
and celebrity worship to math and science, while our gluttonous material
appetite threatens to consume the entire world.
Exactly where and when he wrote this (and to whom) is anybody's guess.
Like it? You can have it for only $23,000.
More on
Neutrino Oscillations
-- Posted by wostraub on Sunday,
February 26 2006
Many people have
written to say that they were fascinated by last week’s PBS program
on neutrinos, The Ghost Particle. It is interesting to note that
Hermann Weyl also made fundamental contributions to our understanding of
these particles, which may be the most numerous things in the universe.
In his seminal 1929 paper, Electron and Gravitation (Zeitschrift
f. Physik, 330 56), Weyl was the first to recognize that the
treatment of spin-1/2 particles (like the neutrino) in a gravitational
field requires a covariant derivative that is appropriate to fermionic
fields.
Weyl’s development of the spin connection ω abλ
and the associated spin covariant derivative emerged from this work, as
was his recognition that the zero-mass version of the Dirac relativistic
electron equation allowed for a description of particles that violate
parity (this is practically the de facto definition of the neutrino!)
While Weyl’s paper preceded Pauli’s 1930 neutrino hypothesis
by a year (and it is doubtful that Weyl had any inkling about the
existence of this particle at the time), his work nevertheless provided a
sound basis for the neutrino’s subsequent mathematical elucidation.
Weyl also was totally unaware of the existence of three types of neutrino
or the possibility of neutrino oscillation, which was the
subject of the PBS program. Whatever the physical process behind a
neutrino’s penchant for converting itself into any of the three
types, it is abundantly clear that a successful description will involve
the dynamics of fermionic fields against a gravitational background, and
this will by necessity involve Weyl’s spin connection and
derivative. Not bad for a mathematican who was once scolded by Pauli for
straying into the physics community!
Several people have asked me about more advanced yet readable information
on neutrino oscillation. I’m the wrong person to ask, because I
know practically nothing! But there are several papers I’ve
collected that have helped me understand the things a tiny bit:
Dieter Brill and John A. Wheeler, Interaction of Neutrinos and
Gravitational Fields (1957). Reviews of Modern Physics, 29
465. [This is probably the first article you should seek out.]
C.Y. Cardall and George M. Fuller, Neutrino Oscillation in Curved
Spacetime: A Heuristic Treatment (1997). Physical Review D,
55 No. 12, 7960.
Xin-Bing Huang, Neutrino Oscillation in de Sitter Spacetime.
arXiv:hep-th/0502165 v1 (12 February 2005).
Victor M. Villalba, Exact Solutions to the Dirac Equation for
Neutrinos Propagating in a Particular Vaidya Background (2001). International
Journal of Theoretical Physics, 40 No. 11, 2025.
The
Ghost Particle on PBS
-- Posted by wostraub on Tuesday,
February 21 2006
I hope you all caught The
Ghost Particle on PBS tonight. The ghost particles are, of course,
neutrinos, first postulated by Wolfgang Pauli in 1930. Nearly massless
and traveling close to the speed of light, approximately 100 trillion
pass through your body every second, and "pierce the lover and his
lass," to quote the famous John Updike poem.
The program chronicles the search for the solar neutrino, and focuses on
the initially-contradicting data between experiment and theory. First
came the theory, proposed by John Bahcall in 1964, that electron
neutrinos would be produced by the sun at a rate of X per
second. Then Ray Davis and colleagues built an apparatus that could
actually measure the things. Strangely, their observations indicated that
the sun was producing neutrinos at the rate of only X/3.
Scientists around the world couldn't figure out just who was right (if
either).
The Standard Model of particle physics says that electron neutrinos are
massless and travel at the speed of light. But in the 1970s and 1980s two
more neutrinos showed up -- the muon neutrino and the tau neutrino.
Today, the family consists of electron neutrinos, muon neutrinos and tau
neutrinos, along with their antimatter counterparts. Most physicists
believe that no new neutrinos will ever be found.
Anyway, to make a long (but very fascinating) story short, it was later
discovered that the three kinds of neutrinos can randomly oscillate
from one kind into another. Thus, the number of solar electron neutrinos
reaching Earth is reduced by a factor of two-thirds. Bahcall's theory was
vindicated, as were Davis' experiments. Both physicists were
right!
Because neutrino oscillation requires that these particles have a
non-zero proper time measure, neutrinos cannot travel at the speed of
light, so they must have a tiny but non-zero mass. Consequently, there
was early conjecture that neutrino mass might account for the
"missing mass" in the observed universe (the total number of
neutrinos in the universe is almost unimaginable, so even a tiny mass
would add up to something truly significant). However, it is now believed
that other, more exotic forms of non-baryonic matter make up the vast
bulk of the known universe's mass-energy. Oddly enough, the ordinary
matter that you and I know and love (protons, neutrons, electrons,
hamburgers, etc.) accounts for only about 5% of the "stuff" of
the universe. The rest is "dark matter" and "dark
energy." Very odd, indeed.
Although Davis (now in his 80s) is suffering from Alzheimer's disease, he
was fully cognizant back in 2002 when, to the delight of his family and
fellow researchers, he won the Nobel Prize in Physics for his neutrino
work. He was accompanied in Stockholm by no fewer than 23 ecstatic family
members -- wife, children and grandchildren. God be praised!
I recorded this excellent PBS program on DVD-R. Let me know if you'd like a copy.
Weyl's
Take on the Gravitational Energy-Momentum Tensor -- Posted by wostraub on Friday, February 17 2006
Shortly after
Einstein's November 1915 announcement of his general theory of
relativity, Weyl attempted to derive a coordinate-invariant form of the
energy-momentum tensor that expressed conservation via an invariant
divergence formula. His failure to find a fully-covariant expression of
this tensor puzzled many physicists at the time. And despite repeated
attmepts over the years by many scientists, no one has discovered a
satisfactory form of the tensor.
This is very odd, because general relativity is practically the de
facto definition of invariance theory, yet something as conceptually
simple as gravitational energy-momentum conservation continues to elude
us.
Weyl's attempt is documented in the first edition of his 1918 book
Space-Time-Matter (Raum-Zeit-Materie). It's a mess, if only
because of the inconsistent index notation he used in those days. But,
yes, a divergenceless energy-momentum tensor can be written down (it
looks like T μν + t μν)
but the quantity t μν is really
only a pseudotensor -- it's not invariant with respect to a change in the
coordinates, and it's not even symmetric with respect to the indices.
This is very frustrating!
Long ago, I thought it might be possible to use Weyl's φ-field
to derive a truly covariant form of the energy-momentum tensor. I failed
in this attempt, but I'm little better than a total idiot, so it's still
possible that this approach is valid. Something to think about on an
otherwise cold and rainy night.
Spin
Connection --
Posted by wostraub on Saturday,
February 11 2006
I rewrote The Spin
Connection in Weyl Space (a somewhat pretentious title, I know) and
included an elementary overview of vector parallel transfer and covariant
differentiation. The .pdf file is posted on the menu to the left. The
typos are all fixed now (I think), but I'm washing my hands of the whole
thing, as it still doesn't read the way I wanted it to. Enjoy it if you
can.
DPGraph -- Posted by wostraub on Monday, January 30 2006
Years
ago when I was teaching, I used a simple but powerful program for creating
static and animated computer graphics called DPGraph. If you have ever
attended university, chances are the program can be downloaded for free
(the site has a list of hundreds of site-licensed universities, and all
you have to do is click on yours [be honest, now] and the program is
automatically downloaded gratis). You can also buy the thing
outright for just $10. Either way, it's a bargain, and it's a blast.
Just enter a 2-D or 3-D algebraic expression on the command line, toss in
a few parameters, and the program gives you fantastic graphics. It's used
by countless schools (including elementary, middle and high schools), but
with a little imagination you can easily create exceedingly-complex
graphics and animations that look like output from a graduate
institution.
The program, which only takes up about 500 KB on your hard drive, will
run on any Windows OS (it also runs on my Mac Powerbook via Virtual PC,
but Virtual PC is such a dog that very high-resolution graphics
[especially animated graphics] take a long time to generate).
The program's documentation is minimal; there's no manual, but the HELP
menu should provide all the information you'll ever need. Also, the
DPGraph website has many hundreds of free downloadable graphics files
that serve as useful examples of the required programming.
DPGraph is a far cry from professional programs like Wolfram's Mathematica,
but that's overkill for most people, anyway (it's also a far cry from my
old Keuffel & Esser sliderule, but that's another story, and I don't
want to date myself too badly here).
"Now
We're All Sons of Bitches" -- Posted by wostraub
on Thursday, January 26 2006
These were the words of
physicist Kenneth Bainbridge to J. Robert Oppenheimer, director of the
Manhattan Project, immediately following the successful test of the
atomic bomb at Alamogordo, New Mexico, on July 16, 1945.
Why my renewed interest in JR? I was looking over a copy of a letter Weyl
had sent to Oppenheimer in 1934, and Weyl practically pleaded with
"Oppie" to accept the directorship of the recently-founded
Institute for Advanced Study (IAS) in Princeton. But Oppenheimer
repeatedly begged off, thinking that he "would be useless" in
such a place.
At the end of the war, with Germany defeated and Japan reeling under two
atomic blasts and the concurrent deaths of 225,000 civilians, both Weyl
and Einstein felt that Oppenheimer was no longer suitable for the IAS
job, and they campaigned for Wolfgang Pauli (who also happened to win the
Nobel Physics Prize that year). Nevertheless, Oppie got the job in April
1947, where he was to remain almost 20 years until his death in early
1967.
My search for a Weyl-Oppenheimer association led me to what is currently
considered the definitive study of the "father of the atomic
bomb" in the new book American Prometheus: The Triumph
and Tragedy of J. Robert Oppenheimer by Kai Bird and Martin J.
Sherwin (Alfred A. Knopf, 2005). The book has little to say about Weyl
(who never worked at Los Alamos), but it gives a detailed account of the
life of Oppenheimer, his early academic triumphs, his success at Los
Alamos, his attempts to internationalize the science of nuclear weapons
to prevent a cold war, the subsequent trials he endured as a suspected
Communist sympathizer and national security threat, and his later life,
which he devoted to sailing, writing, and quiet intellectual pursuits.
True to their nature, the Republicans demonized Oppenheimer as a peacenik
and threat to US unilateral nuclear dominance. Eisenhower had Oppie's
security clearance revoked, and the scientist was scarred by the McCarthy
commie witch-hunt of 1953. It was not until the Democrats had regained
power in 1960 that the US government attempted to patch up its pathetic
relationship with him, and he was eventually awarded numerous honors and
medals by presidents Kennedy and Johnson. It was too little, too late.
Oppenheimer died on 18 February 1967 of throat cancer, much disillusioned
but accepting of his fate.
I remember reading Oppenheimer's obituary in a Time magazine at
my high school library. "Father of the Atomic Bomb" is about
all I remember of it. Later, the noble and wise administrators at Duarte
High School staged an assembly with a guest speaker who spoke to us of
the benefits and charms of fascism and communism. This went on for some
time, while the students all booed and hissed. Only then did the speaker
reveal himself to be a true American patriot whose speech was a sham
designed to expose the manifest evils behind communistic indoctrination.
We all cheered. (I remember this as if it were yesterday.)
While reading the book (I have two other books on Oppenheimer, but this
one's the best), I realize that it's 1953 all over again. Science is
being disparaged, superstition is on the rise, crooked and corrupt
politicians are again in power (perhaps permanently this time), and
Americans have gone into a deep, deep sleep. The warnings of scientists
like Einstein, Weyl, Oppenheimer, Bohr, Serber and many others have been
totally ignored, and as a result the world is far more dangerous today
than ever before. A corrupt, moronic president, in league with a corrupt
but very clever and ambitious Republican Party, false Christians all, is
leading us down the path to destruction. Sons of bitches, indeed.
Collapse -- Posted by wostraub on Sunday, January 22 2006
Take a test tube, fill it
with sterilized nutrient broth, add a few bacteria, and incubate. The
bacteria will multiply exponentially. Their waste products will also
accumulate, and at some point the organisms will enter lag phase, then
undergo death. The bacteria, being insensate organisms, don't know any
better. As long as there's a supply of food and nutrients, they'll
reproduce without any consideration of the possible consequences until
either the food is gone or their wastes destroy their environment.
I've just finished reading Jared Diamond's Collapse: How Societies
Choose to Fail or Succeed (Viking Press, 2005). Diamond, a professor
of geography at UCLA, is a physiologist, evolutionary biologist, and a
biogeographer (whatever that is). He's won numerous awards for his science
and writing, including the MacArthur Foundation Fellowship. He's also the
author of the Pulitzer Award-winning Guns, Germs and Steel. He
is a writer to be reckoned with, and this is a fantastic book.
Collapse decribes the rise and fall of human cultures and
societies like the Easter Islanders, the Maya, the Norse Greenlanders,
the Icelandic Vikings, and our own Southwest American Anasazi. Each one
prospered thanks to plentiful natural resources, but their populations
invariably grew to the point where their respective diminished
environments could no longer support them, and they quickly died off.
Each tells the almost identical story of how population growth destroyed
the cultures' resilience to withstand climate change and periodic
drought. Without exception, each was the victim of a successive pattern
of overextension and environmental destruction, followed by denial,
resource wars, disillusionment, despair and even, near the very end,
cannibalism.
Diamond's first case is the Eastern Island Polynesians, who came to this
remote island (about 2,300 miles due west of Chile) around 900 AD. The
island was small but heavily forested, including a species of vanished
tree called the giant Chilean palm. Birds abounded, as did fish and
shellfish, and the islanders eked out a fairly comfortable living on a
diet based on limited agriculture, local birds, fish, and even porpoises.
For whatever reason, the islanders began a program of competitive
monument building, consisting of huge stone statues called moai
and even larger stone support foundations called ahu. An extinct
volcanic pit furnished an igneous rock that was easily carved, and the
islanders built roads upon which they transported their massive statues
by sheer muscle power. The local giant palms, with heights and diameters
of up to 100 feet and 7 feet respectively, provided the construction
materials needed to build the elaborate system of primitive levers,
cranes and ramps required to raise the statues. Over time, many hundreds
of statues were built.
Within a few hundred years, the forest was completely gone. Erosion wiped
out what little arable soil the islanders had. The birds and porpoises
left, and the fisheries were wiped out. The natives, desperate for food,
turned to cannibalism. All this is irrefutably recorded in the island's
trash heaps and burial mounds.
Ironically, in the last days the few remaining islanders overturned
and/or destroyed the statues, perhaps out of rage that their priests and
elders had deceived them and led them down the path to destruction.
Diamond muses over what that unnamed Easter Islander might have been
thinking as he cut down the island's last tree:
Like modern loggers,
did he shout "Jobs, not trees!"? Or "Technology will solve
our problems, never fear, we'll find a substitute for wood"? Or
"We don't have proof that there aren't palms elsewhere on Easter, we
need more research, your proposed ban on logging is premature and driven
by fear-mongering"?
To this Diamond might
also have added "Don't worry, our gods won't fail us, the Rapture is
coming, and we'll all be saved."
[BTW, for those of you who believe the Rapture is going to bail you out,
you should recall the conversation Jesus had with Satan in Matthew
4:5-7.]
Diamond's book goes on to talk about modern cultures and how many are
following in the exact same footsteps as the above-mentioned ancient
peoples. He gives a few positive examples, like the Japanese, whose
series of islands is still 94% forested, but he overlooks the fact that
the Japanese are preserving their forests by cutting down everyone
else's.
After checking this 570-page book out from the library, I simply could
not put it down, and read it into the wee hours until I was finished.
Diamond is a first-rate writer, and his narratives flow like prose. The
subject material is so appropriate to the here and now that Collapse
should be required reading for all high school and university students.
My only criticism of the book stems from its title, which implies that
cultures can choose to fail or succeed. In my opinion, Diamond does not
give an adequate description of how such decisions can be made, or even
if there's evidence that today's cultures are engaged in such
decision-making. As for me, the whole concept of rational decision-making
lies solely in the minds of people who have been unfairly labeled
liberal, God-hating pessimists. Sadly, the world is ruled by capitalist
exploiters who still think that the Earth's resources are inexhaustible.
I personally see no evidence that Earth's governors are deciding
anything. In spite of our sentience and ability to alter our fate, I fear
we're really no different than bacteria.
Deep
Down Things --
Posted by wostraub on Friday,
January 20 2006
Seduced by the glowing
reviews of UC Santa Cruz physicist Bruce Schumm's new book, Deep Down
Things (Amazon, about $19) and, curious over the fact that the book devotes
almost 80 pages to an elementary elucidation of gauge theory, I bought
the thing and read it.
First off, the book is pretty much aimed at the motivated lay reader who
wants to understand the non-mathematical particulars of the Standard
Model of the electromagnetic and strong and weak nuclear forces (he
wisely left gravity out of the loop because it's clearly beyond the scope
of a book of this kind). The book includes rather extensive (though
elementary) expositions on topics such as Lie groups and Lie algebra,
SU(2) and SU(3) isospin and hypercharge symmetries, the weak interaction
and the quark model, and by book's end I had regained much of what I
invariably tend to forget about this stuff.
However, the book is inconsistent at the levels with which it treats (or
should treat) complex numbers, quantum mechanical phase invariance, and
related topics. For example, Schumm writes down Schrodinger's
one-dimensional wave equation on numerous occasions, explaining what all
the parts represent, but he doesn't feel that the reader is quite up to
understanding the exponential version of complex numbers. This lack of
confidence extends to his description of phase invariance, in which nary
a e i θ appears in the book. This is a shame,
because anyone who has even a smidgen of knowledge about z = a + ib
knows that the exponential form (known as Euler's relation), which is
ubiquitous in quantum mechanics, is easier to use and more intuitive. You
cannot explain to someone what a unitary operator is with z!
Schumm's description of gauge invariance, Weyl's brainchild, is
particularly muddled. The principle of gauge symmetry is easy to
understand, but not if you leave the basic math out of the discussion.
The book's last chapter, Into the Unknown, discusses a few advanced
opics, along with the Higgs field and physicists' hopes to discover it
with the European Large Hadron Collider, which is scheduled to go into
operation in 2007. And while Schumm plays down the role of gravity in all
this, he hints at the possibility that a unified theory of all four
forces will radically change the way we think of everything.
The problem with Schumm's book is the same one that plagues all
popularized expositions of modern physics theories -- there is precious
little middle ground that these writers are willing to explore between a
non-mathematical, golly-gee treatment and a higher-level textbook-like
approach. In my opinion this is not Schumm's fault, but rather that of a
dumbed-down reading public coupled with a rather cynical attitude of the
publishers.
What a
Waste -- Posted by wostraub on Monday, January 16 2006
Here's a morality play
masquerading as a physics problem.
You no doubt know that controlled nuclear fusion would solve the world's
energy problems for all time. Fusion is really very simple -- just get a
deuterium atom and a tritium atom (these are available or easily-made
isotopes of ordinary hydrogen) close enough, and they'll fuse to form
helium-4 (along with a left-over neutron), with the release of lots of
energy. How hard can it be to get two tiny nuclei close to one another?
Well, it's deceptive -- the Coulomb repulsion between the particles is so
great that only truly enormous confinement temperatures and pressures can
get them to fuse. While this has actually been done in gigantic
experimental machines (like the Tokamac), the energy expended in the
experiments far outweighs the energy derived from fusion. Scientists are
still trying to achieve "breakeven," and as a result practical
nuclear fusion is still many decades away.
But there's another way that doesn't require huge pressures and
temperatures.
Take a deuterium-tritium (DT) ion with a single shared electron. Fire a
muon into the ion (the muon is an elementary particle that is identical
to the electron, but about 207 times as heavy). The muon knocks the
electron out of the DT pair and begins to orbit the nuclei, just like its
electron counterpart did. But because of its greater mass, the mean
orbital radius of the muon is 207 times smaller than that of the
electron. This causes the deuterium and tritium nuclei to move very close
to each other. The muon's small orbital radius also effectively shields
the positive Coulombic repulsion of the DT nuclei, which gets them in
even closer. Within a few thousandths of a nanosecond the nuclei undergo
fusion, with the release of about 17.6 MeV of energy. The muon is
unharmed during the fusion event and leaves the helium-4 in search of
another DT pair, where it can do its trick all over again. Because the
muon comes out unscathed, this process is called muon-catalyzed
fusion. It has been demonstrated many times in laboratories over the
past three decades.
So what's wrong with this picture? Nothing, but there are a few technical
problems that have to be overcome. One, muons have to be created, you
can't buy them in stores. They come from decaying negative pi-mesons (or pions,
π-), and you need a linear accelerator to get the
necessary pions. Second, the muon is itself unstable and decays into an
electron, a muon neutrino and an anti-electron neutrino (a muon has a
typical life of only 2 microseconds). And third, once a muon catalyzes a
fusion event, it often develops the habit of hanging around the helium-4
nucleus once it has formed. In view of the muon's short lifetime, this
"stickiness" of the muon wastes valuable time.
However, the first and second difficulties are not all that critical --
they can be dealt with. The most critical problem is the muon's tendency
to loiter around and be unproductive. A means for making unsticky muons
would represent a truly profound discovery and a wonderful gift to
mankind's future welfare.
There's even another particle just like the electron and the muon called
the tau (τ-), which is about 17 times heavier than the
muon. Tau-catalyzed fusion might someday be demonstrated,
although the tau's lifetime is about ten million times shorter than the
muon's.
So what's the upshot of all this? Every year, the world's nations spend
nearly $1 trillion for weapons of war (about half of this amount is spent
by the United States). Recent estimates (by the 2001 Nobel prize winner
in economics, no less) of the actual out-of-pocket costs of the Iraq war
total about $2 trillion Article.
Forgetting annual US defense expenditures, what do you think we could
have done with $2 trillion? Develop practical muon-catalyzed fusion,
maybe? It boggles my mind to think that the US might be able to develop
non-polluting nuclear fusion energy generation if it would only get its
head out of its ass!!
This is just another of President Bush's outrageous legacies -- at a time
when Peak Oil is rapidly approaching, and the country is in desperate
need of an alternative energy source, Bush decides that what we really
need to do is monopolize (i.e., steal) the world's remaining oil
resources! This cannot save us, because even if Europe, China, India and
the other developing countries can be held at bay, the resulting
destruction of the world's economies will also destroy ours. And my guess
is that the other countries of the world wouldn't stand for it --
remember, Russia still has 6,000 nuclear weapons and the missiles to
deliver them.
Make no mistake about it -- the lunatic US Emperor George W. Bush is the
most dangerous man in the world, and we tolerate him at our extreme
peril.
Cosmic
Landscapes --
Posted by wostraub on Sunday,
January 15 2006
In his new book The
Cosmic Landscape: String Theory and the Illusion of Intelligent Design
(Amazon, about $16), Stanford physicist Leonard Susskind suggests that
the universe we inhabit is only one of a nearly infinite number of
"megaverses," perhaps as many as 10500. Each of
these possible universes is based on a different set of fundamental
physical constants, so one universe may permit life while another does
not.
Susskind, a leading string theorist, does not necessarily imply that
intelligent design is wrong, it's just that in his multiverse theory
there's no need for it. Given an almost infinite number of possible
universes, it is inevitable that at least one universe will look just
like the one we live in. And there we are!
For the same reason, Susskind feels that things like beauty and elegance
are also inevitable, especially when a universe contains thinking
creatures. This would seem to imply that there is no such thing as
"absolute truth," which is abhorrent to me, but it's still
something worth thinking about.
Is it possible to flip an "honest" coin 10500 times
in a row and have it come up "heads" each time? Of course! The
probability is very small, but it's not zero. If there are a similar
number of universes out there, all orthogonal to the one we inhabit, the
chances are good that just about any kind of otherwise implausible event
or condition will be observed.
Are these universes the "many mansions" that Jesus spoke about?
Susskind would probably disagree, but I argue that it's equally possible
that it is.
Meanwhile, purely for your enjoyment, here's the Sombrero Galaxy (M104),
located about 50 million light years away from us in the constellation
Virgo. This beautiful galaxy is just one of the hundreds of billions
known to exist in our one universe. God be praised!
Embracing
Lies as Truth -- Posted
by wostraub on Saturday, January
14 2006
I haven't read James
Frey's A Million Little Pieces, and I never will, but I have to
comment on Frey's appearance on Larry King Live three nights
ago. The fuss centers around accusations that Frey's
"redemption" is based on the many lies and half-truths
contained in his book, and the fact that Oprah Winfrey had championed his
book on her book club. The book sold well as a result, but the allegations
are pushing sales beyond Frey's wildest dreams.
Anyway, Winfrey herself called in to King's show to defend Frey and the
book (and her own reputation). Instead of admitting that she had made a
mistake by trumpeting a liar's work of fiction, she made two incredible
claims -- that the book's publisher was to blame for any untruths in the
book, and that she and Frey had apparently created a "new
genre" of legitimate literature, a pleasant blend of fact and
fiction. The ancient adage about turning a sow's ear into a silk purse
comes immediately to mind.
By the way, Frey also brought his mommy along to the King show, no doubt
to throw added weight onto the lies he was spinning.
Anyone who believes Frey's nonsense is a boob, and I guess that includes
Oprah as well as most Americans, many of whom have actively campaigned to
have Winfrey run for president. Winfrey herself seems to be
self-delusional, thinking that her billions are proof that she's
infallible. But the real blame falls on a celebrity-intoxicated American
public that cannot differentiate between truth and lies anymore.
It's no wonder Bush is president.
Teach
Quantum Physics in the Churches? -- Posted by wostraub
on Thursday, January 12 2006
Today, two opposing
members of the Ohio Board of Education appeared on Lou Dobbs Tonight
to present their respective cases for and against the teaching of
intelligent design in Ohio public schools.
Although ID suffered a stinging defeat in Pennsylvania last month, its
adherents are regrouping and taking their arguments to school boards in
numerous states -- Ohio, Georgia, Missouri, Kansas, and even California.
Dobbs listened to both sides, and at one point actually suggested
teaching quantum physics alongside evolution in the schools! He then
asked if it would be proper to teach comparative religion in public
school. The pro-ID guest disagreed, and implied that religious education
had no place in the schools. My read on this is that ID supporters would try
to quietly introduce Christian education into public schools via the
teaching of ID. Apparently, IDers are sold on the idea that intelligent
design belongs solely to the Christian faith; comparative religion be
hanged. I have yet to see a Jew, Muslim or Buddhist demand that ID be
taught as a scientific discipline in public schools.
PBS' Frontline is currently running a series (Country Boys)
on the problems of rural youth -- lack of jobs, premarital sex,
methamphetamine abuse, depression, etc. Last night's episode took us into
a rural Kentucky high school classroom where the teacher ridiculed
evolution as anti-God pseudo-science: "Did Jesus Christ look like an
ape? Do you think you came from a bunch of monkeys? That's not what I
believe!" or words to that effect. I really felt sorry for the
school's students, who undoubtedly have enough problems in their lives.
Now they can add ignorance to the list.
I really like the idea of teaching quantum mechanics (at the appropriate
level) in churches, because QM is undoubtedly one of the tools God uses
to run his universe. Like religion, QM is based on numerous postulates
that cannot be scientifically proven, and so have to be taken on FAITH.
Everyone believes in QM, because modern life could not be possible without
it. Why can't the IDers look at evolution the same way? Evolution is just
one of God's tools to ensure the perpetuation of the planet's species.
But, as Lou Dobbs surmised today, ID ain't going away, and it will
continue to itself evolve until it is absolutely disproven as a science
and banned outright or legitimized and made a mainstay in the public
schools. Hopefully, the legitimization of ID, like evolution, will also
take millions of years.
Fascinating
Physics -- Posted
by wostraub on Saturday, January 7
2006
A hydrogen atom is just
an electron bound to a proton. What if you replace the proton with some
other positively-charged particle?
If that particle is an antielectron (or positron), you get
something called positronium, or Ps. Physics Today rightly calls
it "nature's simplest atom."
Electron/positron pairs are created near charged particles, but they
invariably annihilate one another, resulting in photon pairs. But under the
right circumstances, and for intervals on the order of 100 nanoseconds,
they join to form Ps. There are two bosonic species of Ps: ortho-Ps, in
which the particle spins are aligned (spin one), and para-Ps, in which
the spins cancel (spin zero).
The latest issue of Physics Today (January 2006) reports that researchers
at the University of California at Riverside have found indirect evidence
that two Ps atoms can join to form a diatomic molecule (Ps2).
If confirmed, the researchers believe that they can form a Bose-Einstein
condensate at a temperature of around 15 degrees K. This in turn might
then lead to gamma-ray lasers in which each photon has an energy of about
0.5 MeV. Amazing!
I imagine even George W. Bush will be interested in this, but for another
reason -- gamma-ray space lasers to zap the evil-doers (set your weapon
to deep fat fry, comrade!)
To The
Mall, Patriots! --
Posted by wostraub on Saturday,
January 7 2006
I laughed out loud when
I read Jesse Eisinger's WSJ article about neoconsumerism under the Bush
Reign of Terror. He calls it zombie consumerism -- for a reason
you'll need to read the article to understand.
Eisinger points out that for the first time since the Great Depression,
Americans spent more money in 2005 than they earned. This negative cash
flow greatly increased the nation's debt, as Americans flocked to take
out home equity loans to pay for all their SUVs, gadgets and credit card
installments (I guess they see this as "found money" that
doesn't have to be paid back). I peeked in on the Commerce Department's
website back in November, and it confirmed that Americans were indeed
saving nothing but spending nevertheless.
Eisinger warns that with the flattening of the real estate market, record
bankruptcy rates, usury-like credit interest rates, the spiraling
differential between workers' pay and lavish CEO pay, and the very real
connection between stock market performance and the availability of
consumer cash, the future bodes ill for Bush's wundereconomy. WSJ Article
Weyl on
Time Travel --
Posted by wostraub on Saturday,
January 7 2006
While slaving away at
the gym this morning, I started to think about time travel again. This is
one of my favorite topics, in spite of the fact that I really don't think
it's possible, at least for any massive object.
If you check out the New Testament, you'll see numerous references to God
and light. I believe this connection is more than just hyperbole, because
if God is purely spiritual then he undoubtedly moves on a null
geodesic, which is to say that he is free to move around just like a
photon of light.
A photon lives is a very strange world, indeed. Because its line element
vanishes (ds2 = gμν dxμdxν
= 0), it exists everywhere in the universe at all times -- past,
present and future. This fact is paradoxical to us humans, because when
we snap on a light, photons are created at that instant, and when they
are absorbed by our cornea, they are annihilated. Clearly, then, light
can be created and destroyed in a short time interval. But a photon's own
existence is much different -- to a photon, it is people whose
lives are sedentary and fleeting. This is nothing more than an extreme
example of Einstein's so-called twin paradox, which of course is
not a paradox at all when you've understood special relativity. So the
saying "God is light" is probably closer to the truth than one
usually imagines.
In 1994, the noted Caltech physicist Kip S. Thorne published his wonderful
book Black Holes and Time Warps -- Einstein's Outrageous Legacy.
Mostly a non-mathematical look at time travel through wormholes and the
like, it's a fascinating read that investigates various time travel
possibilities along with their inherent problems and paradoxes. Following
one of his promotional lectures (I think it was one of the Leon Pape
Lectures), I got the chance to talk to Thorne about time travel, quantum
field theory, relativity, and life in general. But when I asked him if he
himself believed in time travel, I got an elusive answer.
[By the way, I took along a copy of Thorne's 1965 first book Gravitational
Theory and Gravitational Collapse. He signed it for me, and told me
that he still gets a miniscule royalty check from the publishers each
year from the half-dozen or so copies that they sell.]
Thorne and his British pals and colleagues Stephen Hawking and Roger
Penrose are arguably the world's foremost authorities on time travel. But
many years ago, our good friend Hermann Weyl also speculated on the
time-travel possibilities associated with a rotating universe:
It is possible to
experience events now that will in part be an effect of my future
resolves and actions. Moreover, it is not impossible for a world line (in
particular, that of my body), although it has a time-like direction at
every point, to return to the neighborhood of a point which it has
already once passed through ... In actual fact the very considerable
fluctuations of [the metric tensor gμν]
that would be necessary to produce this effect do not occur in the region
of the world in which we live. Although paradoxes of this kind appear,
nowhere do we find any real contradiction to the facts directly presented
to us in experience.
In fact, Weyl took the
rather extreme view that the very concept of time is illusory and an
inherent debilitation of the human mind. He once famously remarked
The objective world
simply is, it does not happen. Only to the gaze of my
consciousness, crawling upward along the world-line of my body, does a
section of the world come to life as a fleeting image in space which
continuously changes in time.
Before you dismiss
these words as overly metaphysical, consider the remarks of St. Thomas
Aquinas (or was it St. Augustine?), who "knew what time is except
when asked what it is." What really is time? Einstein
treated it as the fourth dimension, but it's obviously not just another
coordinate. My guess is that we will never really know until we stand
before God. But will time still exist then?
The concept of time not existing (which must have been the case
"before" the Big Bang) is not so far-fetched because if time
doesn't exist there can be no causal loops or other time-related
paradoxes. A universe without time might not be such a bad place. At least
we wouldn't get old and decrepit!
On a perhaps more realistic note, consider this. Let's say that you want
to travel back to Northside Square in Bolivar, Missouri at exactly 5:00
pm CST on November 5, 1955 (like Professor Brown in Back to the
Future). You get into your Way Back machine, set the dials on the
flux capacitor, and hit the "go" button. An instant later, you
materialize in the vacuum of empty interstellar space, where you quickly
decompress and die. What went wrong?
The problem is due to the fact that Earth was not at the location you've
traveled to in time. Because the Earth is rotating on its axis and moving
around in the solar system (which is also moving in the Milky Way Galaxy,
which is also moving relative to the Local Cluster), you don't want a
time machine. What you want is a spacetime machine, a device
that will take you both when and where you want to go.
This means that you have to know the precise spacetime coordinates of
your destination, otherwise you're likely to end up in airless space or
physically embedded in a tree or mountain. To get these coordinates, you
need to have the world line (4-D history) of the travel-to location. But
where are the world lines of all physical objects and locations in the
universe maintained?
I don't believe that UFOs are Little Green Men; I prefer to believe that
(if they exist at all) they are time-traveling historians or scientists
who, for whatever reason, prefer to remain undetected. If way-back time
travel is at all possible, future travelers in their spaceships will know
that it is far safer to approach Earth from space, where any imprecision
in their spacetime coordinates won't matter (unless they happen to
materialize within an asteroid, but then space travel is an
adventure, isn't it?)
The best reference I've found on the subject is the 1993 book Time
Machines by Paul J. Nahin, a professor of electrical engineering at
the University of New Hampshire. It's still available in paperback, and
it's excellent.
Hermann
Weyl and CPT Symmetry -- Posted by wostraub on Saturday, December 15
2007
As I noted earlier, I
managed to locate a copy of Hermann Weyl's Zaum — Zeit
— Materie: A General Introduction to His Scientific Work, and
I'm still making my way through it. A considerable portion of the book
is in German which — contrary to popular belief — I am only
moderately fluent in, so it's taking some time.
Weyl seems to have been in love with group theory, especially the
continuous Lie groups (SU(2), SU(3), and all that) and he appears to
have concentrated the latter part of his life on this topic, along with
other subjects in pure mathematics. His earlier interests in general
relativity, cosmology and philosophy seem to have waned during this
time of his life, and it leads me to wonder how his immigration to
America in November 1933 might have affected his professional
inclinations.
At any rate, I find Weyl's mathematics (unlike his physics) to be very
difficult and hard to follow. But there is one thing that jumps out of
the book at me, and that involves the following questions:
Why does mathematics
describe the physical world so well? Why should Nature obey the laws of
mathematical symmetries? Why does group theory govern so much of what
goes on in the world?
These are hardly new
questions, but the answers seem to be just as far from us today as they
were in Weyl's time.
Even more intriguing is the fact that Weyl, in 1929, was able to deduce
that Nature should also obey the discrete symmetries described
by charge, parity and time (CPT) invariance. Even today, we haven't the
slightest idea why God decided that these symmetries should carry so
much power and influence over Nature. In a later edition of his 1928
book Group Theory and Quantum Mechanics, Weyl wrote
The problem of the
proton and the electron is discussed in connection with the symmetry
properties of the quantum laws with respect to the interchange of right
and left [parity invariance], past and future [time invariance], and
positive and negative electricity [charge invariance]. At present, no
acceptable solution is in sight; I fear, that in the context of this
problem, the clouds are rolling together to form a new, serious crisis
in quantum mechanics.
Weyl's analysis of
the Dirac and Maxwell equations in the context of combined CPT symmetry led him to the correct conclusion
that the mass of the then newly-discovered positron (the anti-electron)
should be identical to that of the electron. The "crisis"
that Weyl referred to involved the then-prevailing opinion that the
positron should be nothing more than the familiar proton, whose mass
exceeds that of the electron by a factor of almost 2,000. Of course, we
now know that there was no crisis at all. But the reason why CPT symmetry mandates these kinds of physical
consequences remains a total mystery.
God
and the Many-Worlds Interpretation of Quantum Mechanics -- Posted by wostraub on Monday, December 3 2007
I apologize for this
overly-long post.
This month’s Scientific
American (it’s becoming an oxymoron, isn’t it?) has
a fascinating article about Hugh Everett III, the late physicist whose 1956 PhD
dissertation formalized the idea of parallel universes. And once again
we see the hand of the noted physicist John Archibald Wheeler (see my
earlier post), who was Everett’s academic advisor at Princeton
University. Wheeler, apparently enthralled by the multi-universe concept,
went to Copenhagen to discuss the idea with the great Niels Bohr, no
less, who, unfortunately, didn’t like the theory. Wheeler
returned to Princeton and coerced Everett into paring down his
dissertation to make it more conventionally acceptable. The PhD, which
was finally awarded to Everett in 1957, was a shadow of its former
self, but it nevertheless succeeded in bringing the idea of parallel
universes into the scientific world.
Hugh Everett, 1930-1982
Everett’s idea (which is now called the many-worlds
interpretation of quantum mechanics) is pretty bizarre. But for
reasons I will explain shortly, it deserves serious consideration.
The basic idea is very simple. The Schrödinger equation says that the
wave function Ψ of an object represents a superposition of
possible physical states (rather like a complicated musical sound wave
that consists of a linear combination of individual waves). The wave
function is a complex-valued quantity, which means that it is
essentially unobservable until a measurement is made. Then it collapses
probabilistically but uniquely into one of its allowable states;
the resulting state is a real-valued quantity, and is the one we humans
can actually observe with our eyes and ears. Wave function collapse is
one of the central pillars of what is known as the Copenhagen
interpretation of quantum mechanics.
But since its development in the late 1920s, the Copenhagen
interpretation has dogged physicists with the whole collapse idea. How
does observation (which can be a very “gentle” process)
bring about collapse? Does it take an intelligent entity to collapse a
wave function? Can a mouse collapse a wave function? Why can’t we
see a quantum-mechanical superposition of states? Why just one? These
aren’t just idle musings; they involve the very foundation of
that slippery thing we call reality.
Everett was also bothered by these questions, and he considered what
might happen if a measurement doesn’t collapse a wave
function. The conclusion was inescapable — incredulous as it
sounds, if you flip a coin and get heads, then the universe must split
off another universe in which a parallel YOU gets tails. Similarly, if
you measure the energy state of a free particle (which has an infinite
number of superposed energy states), an infinite number of universes is
created, one for each possible observation. In both cases, the wave
function remains intact and uncollapsed, and the only price we have to
pay for this is our sanity!
(Everett went even farther than what I've sketched above. His original
PhD thesis dealt with a continuously-evolving wave function for the
entire universe, and included the observer as an intrinsic quantum
participant in the overall observation process.)
The main reason this SciAm article aroused my interest is because I
just finished reading Frank Tipler’s latest book, The
Physics of Christianity. Tipler, a highly respected (and
apparently even sane) mathematical physicist at Tulane University,
wrote a similar (and more mathematical) book called The Physics of
Immortality, and his latest effort is a slightly more refined
follow-up. Basically, Tipler’s thesis is this: the Trinity of
God, Jesus Christ and the Holy Spirit is all that Christianity says it
is, and Everett’s many-worlds interpretation (MWI) proves it.
Assuming you are a relatively sane person, even a casual glance at
Tipler’s writings will lift your eyebrows. I don’t for a
minute accept a lot of what he says, despite really, really trying to
follow his mathematical logic. But here’s something to consider: the
majority (60%) of the world’s notable physicists believe (often
grudgingly) that the MWI is either certainly true or probably true
(see this reference).
A few of their comments:
I think we are forced
to accept the MWI if quantum mechanics is true. — Richard
Feynman, Physics Nobel Laureate
I don’t see any way to avoid the MWI, but I wish someone would
discover a way out. — Leon Lederman, Physics Nobel Laureate
I’m afraid I do [believe in the MWI]. I agree with John Archibald
Wheeler, who once said that it is too much philosophical baggage to
carry around, but I can’t see how to avoid carrying that baggage.
— Philip Anderson, Physics Nobel Laureate
The MWI is okay. — Murray Gell-Mann, Physics Nobel Laureate
The MWI is trivially true. — Stephen Hawking
For what it is worth [I prefer the MWI over the Copenhagen
interpretation]. — Steven Weinberg, Physics Nobel Laureate
To this list, Tipler
adds another authority:
Jesus answered,
“My kingdom is not of this world.” — John 18:36
Tipler could have
also added:
“In my
Father’s house are many mansions …” — John 14:2
I need to shut this
down now, but lastly consider this: Tipler believes that God is not a
magician, only (only!) an eternal and very clever physicist and
mathematician who has figured everything out. If we can believe that
God fashioned Eve out of a rib bone he yanked from Adam, we can surely
believe in Everett’s many-worlds theory. I urge you to read The
Physics of Christianity and decide for yourself.
Weyl, Wheeler
and Wormholes --
Posted by wostraub on Sunday,
December 2 2007
I've been reading Hermann
Weyl's Raum-Zeit-Materie and a General Introduction to his Scientific
Work, a neat collection of articles by noted Weylophiles Erhard
Scholz, Skuli Sigurdsson, Hubert Goenner, Norbert Straumann, Robert
Coleman and Herbert Korte. Having recently re-read Kip Thorne's book
on wormholes, I was struck by a comment made by Coleman and Korte regarding
Weyl's supposed "discovery" of the wormhole idea.
On Pages 198 and 199 of the book the writers provide a short list of
Weyl's accomplishments, including his "invention of the wormhole
concept in connection with his analysis of mass in terms of
electromagnetic field energy." Since Thorne does not even mention
Weyl in his book, I pulled Weyl's Space-Time-Matter off my
shelf and went through it with a fine-toothed comb. Yes, Weyl talks at
length there about electrodynamics and the problem of matter (and
there's some discussion of "world canals" in Section 36), but
I'll be damned if I can find anything remotely related to the wormhole
concept.
Thorne has demonstrated that wormholes almost certainly cannot exist
but, if they do, they would require a kind of negative-pressure exotic
matter to keep them from collapsing. Nowhere in Thorne's book do I
see any primary role for electromagnetism in relationship with this
exotic matter.
I can imagine that, when Karl Schwarzschild wrote down the first exact
solution to Einstein's gravitational field equations in 1916, the
concept of a black hole (a term coined by John Wheeler in
1967) may have crossed his mind. However, black holes were quickly
dismissed in those early days, and it is not hard to suppose that the
idea of a wormhole (a term also coined by Wheeler in 1957) had not even
been dreamed about.
I give Weyl credit for many wonderful ideas, but I don't think
wormholes can be included on that list.
Not
Even Wrong --
Posted by wostraub on Monday,
November 5 2007
Wolfgang Pauli (1900-1958),
the Austrian physics Wunderkind of the early-mid 20th century,
often intimidated younger, inexperienced physicists by declaring their
ideas ganz falsch, or "utterly wrong." Those who he
really zeroed in on suffered the rather more blistering comment nicht
falsch, or "not even wrong."
Not
Even Wrong is the title of Peter Woit's poison pen-letter
to string theory (and also the title of his fascinating website).
Woit, a noted Columbia University physics lecturer who likens the
untestable string theory to a kind of religion, feels that the theory's
promise to unite the four fundamental forces of nature is nothing more
than hope disguised as hyped progress.
Although the Standard Model of physics successfully unifies all of
quantum theory with electrodynamics, it does so at the expense of
assuming all kinds of physical constants that it cannot account for.
But its most glaring oversight lies in the fact that it cannot
incorporate Einstein's gravitation theory into the mix. To date, the
Standard Model is 100% accurate in terms of its predictions of
experimental quantum results, but it can tell us nothing about gravity.
Over the past 90 years, gravity has steadfastly refused to associate
itself with quantum theory despite the efforts of literally thousands
of physicists, including Einstein himself (who spent the last 30 years
of his life in the effort). The curmudgeonly Pauli himself also tried
in vain, and finally declared that "what God hath put asunder, let
no man join."
Woit's book is a great introduction to the Standard Model, including
quantum field theory, but his description of the details of string
theory is necessarily lacking, if only because the theory's mathematics
is maddeningly difficult.
But as simplistic as it is, Woit's book has made me wonder if the ideas
of Truth and Beauty, which I have always assumed to be identical, truly
hold up. Although my own understanding of the mathematical details of
string theory is limited, the parts I do understand are truly
beautiful, and like many others I have tacitly assumed that string
theory is too beautiful a concept for God to have overlooked.
But Woit warns us not to be overly impressed with Beauty alone, because
it does not necessarily represent Truth. I had often suspected this,
noting the concept of broken symmetry in quantum mechanics — if
God's physical laws were perfect, then quantum symmetry could not be
broken. It seems that although God started out with a great idea, he
found it impractical — some imperfection is needed in the
universe, if only to make things interesting. It goes without saying
that God made mankind imperfect, but I believe he did this
intentionally in order to give us free thought. Exactly why God gave us
this gift or, for that matter, why he even gives a damn about us, is a
profound mystery.
Woit considers string theory to be an "ossified ideology,"
and recommends that scientists now move on toward a fuller
understanding of quantum field theory and its relationship to
mathematics. Will string theory prove to be a waste of time and effort?
Even if it is, it at least has given us a glimpse into the mind of God,
which probably cannot be understood anyway.
Insects
and Worldlines --
Posted by wostraub on Sunday,
October 28 2007
2005, the "Year
of Physics," brought about the appearance of I don't know how many
more books on Einstein, no doubt inspired by the 100th anniversary of
Einstein's annus mirabilis, 1905, the wonder year in which the
26-year-old Swiss patent clerk cum world-renowned scientist produced
four papers that would forever change physics.
Now another book has appeared. Albert Einstein: The
Persistent Illusion of Transience (edited by Ze'ev Rosenkranz and
Barbara Wolff), is too slim (264 pages) to qualify as a coffee-table
book, but its high-quality photographs of its subject more than make up
for the book's brevity. I'm not sure that it really adds anything that
we didn't already know about the man, but it's nice to see that people
are still interested in him and his science.
Einstein used to quip that his fame grew out of his awareness of
something that had escaped most people (and insects):
When the blind
beetle crawls over the surface of a world globe, he doesn't realize
that the track he makes [a
"worldline" or geodesic] is curved. I was lucky enough to
have spotted it.
In their very
comprehensive (and, at nearly 1,300 pages, very long) 1973 foundation
text Gravitation, Misner, Thorne and Wheeler also spotted it,
this time using the analogy of an ant crawling over the surface of a
piece of fruit ("The Parable of the Apple"):
It was the very first graphic in this book (above) that caught my eye
one day in 1975, when I spotted the text on the shelves of the
miniscule public library in Lone Pine, California. Widely viewed as the
standard graduate-level text on general relativity, I wondered how in
hell it had landed in a tiny town whose only claim to fame was that, as
the portal to Mt. Whitney, it had hosted Humphrey Bogart and company
during the filming of the 1940 classic High Sierra. The book
was my companion on a day-long hike up the 14,000-foot mountain during
that glorious summer that I discovered the miracle of general
relativity. It also brought me closer to God, whose miracles and
wonders I continue to marvel at.
The
Fox and the Forest
-- Posted by wostraub on
Tuesday, October 2 2007
Roger and Ann Kristen
are government scientists, developing leprosy bombs and other high-tech
disease-culture weaponry for a war that never seems to end. Unlike most
American patriots in the fascist country of the United States in the
year 2155, they hate what they do. They hate the killing, the
fear-mongering, the torture, the constant propaganda, the all-pervading
culture of death.
But they play along, and eventually they are rewarded with a vacation
courtesy of the government-sponsored Travel in Time, Inc. Of course,
they have to put up a bond and leave all their assets in government
hands as assurance they will return after their time vacation. But
where to go? They decide on New York City, 1938.
But Roger and Ann have no intention of staying in New York, nor do they
plan to return to their own time. They run off to Mexico City, where
they adopt the names Bill and Susan Travis. They've managed to take
with them a small fortune in travelers checks, and plan to live out
their lives in total anonymity, away from the horrors of 2155. They
carefully erase all evidence of their escape, hoping they'll find peace
in another place, another time.
Unfortunately for these little rabbits on the run, there's also a fox
in the forest of time.
This is the premise of Ray Bradbury's brilliantly disturbing 1950 short
story, The Fox and the Forest, which is reprinted in his
collection of short stories, The Illustrated Man. It may even
be on the Internet somewhere. At any rate, you should read it.
Bradbury is now 87 years old. I saw him frequently at the old Vagabond
Theatre in Los Angeles in the late 1960s, where they used to run
science fiction movies and silent films. He was a friendly,
approachable guy who clearly loved his medium, which was mostly science
fiction, fantasy and eccentric horror. Bradbury's The Fox and the
Forest, The Lake, and The Small Assassin are irreducible
masterpieces. I wish there were more writers of his caliber today. Or,
at the very least, more writers with a moral sense.
Where would I go? Probably Europe in the mid-1920s. Or Victorian
England.
Dear God in Heaven, anywhere but here and now.
Wolfgang
Panofsky Dead at 88
-- Posted by wostraub on
Thursday, September 27 2007
Stanford University's
Wolfgang Panofsky is dead. The father of Stanford's linear electron
accelerator and one of the discoverers of the neutral π
meson, Panofsky was also noted for his abhorrence of nuclear weapons
and their proliferation.
I remember a soft-spoken, kindly, balding Panofsky at a 2004 lecture he
gave in Los Angeles. His entire talk was about nuclear proliferation
and ways of reducing or eliminating the spread of nuclear weapons, and
I recall being touched by the compassion the man felt toward humanity
and the underlying sadness he felt about the seeming inevitability of
mankind's willingness to wage war and the role that nuclear weapons
would ever play in that insanity.
Panofsky was born in Berlin in April 1919. A family of intellectual
Jews, the Panofskys left Nazi Germany in 1935 fearing for their lives.
Wolfgang's father, a noted art historian, took up teaching at Columbia
University and the Institute for Advanced Study. Wolfgang and his older
brother were of high school age in Germany but were accepted at
Princeton, where Wolfgang majored in physics. Graduating at the age of
19, he then went to Caltech in 1938 after receiving a personal
invitation from the school's president, Nobel Laureate Robert Millikan.
Panofsky received his physics PhD in 1942 but, being a native German,
was declared an enemy alien under California's Alien Exclusion Law.
Millikan came to his defense, however, and Panofsky was granted naturalized
citizenship.
He then went on to consult for the Manhattan Project in New Mexico,
where he personally witnessed the Trinity bomb test from a B-29 bomber
on July 16, 1945.
During a stint at UC Berkeley during the McCarthy era, Panofsky abruptly
resigned after being coerced into signing a loyalty oath. He
subsequently made his way to Stanford, where he distinguished himself
not only in groundbreaking accelerator physics but in world peace. He
was instrumental in developing the Atmospheric Test Ban Treaty of 1963
and, in 1972, the Antiballistic Missile Treaty.
He leaves his wife of 65 years, Adele, five children, eleven
grandchildren, and two great-grandchildren.
There are so few of the great physicists like Panofsky still alive
today. God bless him, and may we all meet with peacemakers like him in
heaven.
The
Connection (Γ αμν)
Again -- Posted
by wostraub on Tuesday,
September 18 2007
In 1918 Hermann Weyl tried
to unify gravity and electromagnetism by a generalization of Riemannian
geometry. He did this by eliminating the notion that the magnitude of a
vector is invariant with respect to parallel transport. In doing so, he
was forced to identify the electromagnetic 4-potential with a non-zero
covariant derivative of the metric tensor.
Subsequent to this effort, numerous other prominent physicists tried
their hand at the unification game, which at the time was simplified by
the fact that only two forces were then known — gravitation and
electrodynamics. Einstein, Kaluza, Eddington, Pauli and Schrödinger
each took their turns and, ultimately, their lumps.
Weyl’s effort remains notable for the fact that the geometry that
describes his unification is invariant which regard to a local gauge
variation of the metric tensor; this idea failed, but in 1929 Weyl
applied the gauge concept to quantum mechanics, where it found a home.
But why does the gauge idea work for the wave function and not the
metric tensor?
The most obvious answer has to do with the fact that the wave function Ψ(x,t)
is a complex-valued quantity whose meaning is clear only when its
conjugate square Ψ*Ψ is taken. Even then,
this square (though real) can only be understood as a probability. By
comparison, the wave function by itself is at best a probability
amplitude. The metric tensor gμν, on
the other hand, is a purely real quantity that needs no
“squaring.” Similarly, the invariant line element ds2
= gμν dxμdxν,
which measures the interval between events in spacetime, is also a real
quantity.
On the basis of Einstein’s criticism that the line element itself
should be invariant with respect to gauge variations (but isn’t
in Weyl’s geometry), Weyl decided to adjust the metric tensor via
an exponential scale factor
gμν → exp [ k ∫φμ
dxμ ] gμν
where k is a constant and φμ is
the Weyl vector (which he associated with the 4-potential). Weyl knew
that in quantum mechanics this vector was a complex quantity;
consequently, the adjusted metric tensor and the line element could be
made gauge invariant by a suitable choice of the constant k.
Thus, it is (gμν*gμν)1/2,
and not gμν, that must be taken as real.
The Weyl scale factor makes for some interesting physics, but its presence
in Lagrangian actions introduces an integral term that is hard to
interpret (it actually prevents the derivation of classical,
tried-and-true equations of motion).
Eddington was aware of this defect, and in response he decided that the
metric tensor should not be taken as the fundamental quantity. Instead,
he chose to develop a theory based on the affine connection,
which defines the parallel transport of vectors (the concept of a
connection was first proposed by Cartan, and later expanded by Weyl).
In Weyl’s original theory the connection term has φμ
embedded in it, which makes the connection complex-valued. (Indeed, the
terms making up the connection are to a large extent arbitrary; the
connection only collapses to the usual Christoffel definition when a
Riemannian manifold is imposed.)
This renewed focus on the connection term motivated Einstein and others
to consider a connection that is non-symmetrical in its two lower
indices. Indeed, the so-called theory of the non-symmetrical field
occupied Einstein for the last decade or so of his life. Most
physicists today consider the theory to have been a tragic waste of the
great scientist’s time and effort.
The connection term is still an open topic in mathematical physics and
differential geometry. If we do not impose the demand of a Riemannian
manifold, its precise makeup is largely arbitrary. Is this how quantum
effects enter into gravitation, as Weyl and Einstein had hoped?
Probably not, although it can be argued that a connection describing internal
spaces, possibly in multiple spacetime dimensions obeying higher
gauge symmetries, may yet find application in the description of a
consistent quantum gravity theory.
Ramanujan -- Posted by wostraub on Saturday, September 8
2007
I just finished
reading Robert Kanigel's award-winning 1991 book The Man Who Knew
Infinity: A Life of the Genius Ramanujan. The book's
great length stands in stark contrast to the very brief life of its
subject, the largely self-taught Tamil mathematician Srinivasa
Ramanujan, who died in 1920 at the age of 32.
Ramanujan's genius was saved from obscurity by the noted British
mathematician Godfrey Hardy, who brought the 25-year-old to Trinity
College in 1913 and served as the younger man's mentor until
Ramanujan's death by tuberculosis seven years later. Although devoted
to Ramanujan, the book is almost equally a tribute to Hardy who, unlike
many other noted scholars in his circle, saw Ramanujan as an equal and
not as a talented but inferior person of color.
The book does not overlook the profound tragedy of genius cut off at an
early age, and the author ponders what heights Ramanujan might have attained
if he had lived longer. Ramanujan was particularly adept at evaluating
truly complicated improper integrals, and I could not help but wonder
what luck the mathematician might have had with the
infinite-dimensional path integral of quantum field theory, which can
only be solved perturbatively.
A devout Hindu, Ramanujan saw a divine hand in all mathematical
expressions. "An equation for me has no meaning," he wrote,
"unless it expresses a thought of God."
UPDATE. There's a new book
out based on the life of Ramanujan.
Why
Gödel Thought US Dictatorship Possible -- Posted by wostraub on Tuesday, September 4
2007
In his 2005 book A
World Without Time, Brandais University philosophy professor Palle
Yourgrau writes
Years later,
asked for a legal analogy for his incompleteness theorem, [Gödel] would
comment that a country that depended entirely upon the formal letter of
its laws might well find itself defenseless against a crisis that had
not, and could not, have been foreseen in its legal code. The analogue
of his incompleteness theorem, applied to the law, would guarantee that
for any legal code, even if intended to be fully explicit and complete,
there would always be judgments "undecided" by the letter of
the law.
If this is indeed how
Gödel felt, then he unequivocally predicted that an event like 9/11
could plunge the United States into a dictatorship, an outcome that the
Founding Fathers simply could not have foreseen.
[Gödel's later years were plagued by paranoia and hypochondria. Fearing
that he would be poisoned by hospital doctors, he stopped eating and
died in 1978 of self-imposed starvation. At the end, he weighed 65
pounds.]
We Americans are always bragging about how brilliant the Founding
Fathers were in drafting the US Constitution. But I believe that Gödel
was absolutely right -- the Founders could not have foreseen that their
country would utilize an event (largely brought upon by itself) as an
excuse to give the president dictatorial powers. And this is exactly
what has happened.
Kurt
Gödel and the US Constitution -- Posted by wostraub
on Friday, August 31 2007
I noted in my
previous post that in 1949 the brilliant Austrian-American mathematical
logician Kurt Gödel had discovered a solution to Einstein's field
equations that allowed for time travel. His discovery was presented to
Einstein on the occasion of the latter's 70th birthday party. (See my
September 25, 2005 post for more info.)
Kurt Gödel and friend, early 1950s
I neglected to mention that a year earlier Gödel believed he had
discovered a logical inconsistency in the US Constitution that allowed
for the establishment of a dictatorship in America -- and told a
federal judge about it!
The story, which is true, has Gödel traveling by car with his Princeton
colleagues Albert Einstein and economist Oskar Morgenstern to Trenton,
New Jersey, where Gödel was to be sworn in for his US citizenship.
During the drive, Gödel expressed his concern that an inconsistency in
the US Constitution allowed for a dictatorship to be imposed on the
American people. Einstein and Morgenstern told him not to worry about
it.
The attending federal judge had earlier sworn in Einstein, and he
invited the distinguished trio into his chambers for a pre-swear-in
chat. The judge happily informed Gödel that, unlike war-time Germany, a
dictatorship could never happen in America. At this point an agitated
Gödel blurted "Yes, it can! I've discovered a loophole in the Constitution
that allows for a dictator to take over the country!" or words to
that effect.
Einstein and Morgenstern were able to defuse the situation, however,
and Gödel was duly sworn in.
I've heard this story many times, but I've never heard the basis for
Gödel's argument. Some think it's Article 5, which allows for
amendments. Others think it involves the establishment of executive
powers. But I'm not a lawyer, and despite a careful reading of the
Constitution I can't even imagine what might have concerned Gödel.
But I fear he was right all along. (I'll omit my usual anti-Bush rants,
as you all probably know of which I speak.)
Anyone know more about this story? If you're an armchair Constitutional
theorist, I'd be happy to hear from you.
UPDATE: Several readers directed me to this: New
Yorker Article, but it still doesn't explain why Gödel thought
the Constitution was flawed.
Good
Bye to Clocks Ticking -- Posted by wostraub
on Thursday, August 30 2007
I can't go on. It
goes so fast. We don't have time to look at one another. I didn't
realize. So all that was going on and we never noticed. Take me back
— up the hill — to my grave. But first: Wait! One more
look. Good-by, Good-by, world. Good-by Grover's Corners ... Mama and
Papa. Good-by to clocks ticking ... and Mama's sunflowers. And food and
coffee. And new ironed dresses and hot baths ... and sleeping and
waking up. Oh, Earth, you're too wonderful for anybody to realize you!
Do human beings ever realize life while they live it? — Every,
every minute? ... I'm ready to go back ... I should have listened to
you. That's all human beings are! Just blind people.
— Emily Webb to the Stage Manager in Thornton Wilder's Our
Town
The newly-deceased
Emily got her wish to travel back in time to witness her 12th birthday.
Did Weyl ever wonder about time travel? Indeed, he did. Thirty years
before Kurt Gödel's 1949 discovery that a rotating universe could
enable travel backward in time, Weyl wrote
It is possible to
experience events now that will in part be an effect of my future
resolves and actions. Moreover, it is not impossible for a world-line
(in particular, that of my body) — although it has a time-like
direction — to return to the neighborhood of a world-line point
which it already once passed through. The result would be a spectral
image of the world more fearful than anything the weird fantasy of E.
Hoffmann [an eccentric 19th-century German writer] has ever conjured
up. In actual fact the very considerable fluctuations of the components
of the metric tensor needed to produce this effect do not occur in the
region of the world in which we live. Although paradoxes of this kind
appear, nowhere do we find any real contradiction to the facts directly
presented to us in experience.
No doubt, Weyl (like
Einstein) did not believe in super-luminal velocities, so that mode of
time travel to the past was verboten. Also, Weyl probably
never heard of wormholes, so that idea was out, too. That left motion
about the spacetime surrounding a rotating massive body. Although Weyl
died eight years before the physicist Roy Kerr discovered the exact
metric describing a spherical, chargeless rotating mass, he was aware
of the theoretical work of Lense and Thirring, who in 1918 were able to
deduce the approximate field of a rotating body. Today, this effect is
called frame-dragging.
Weyl knew that the field of a sufficiently massive body undergoing a
high rate of rotation would cause the light cones of a test particle
moving in the direction of rotation to tip over in the same direction,
thus creating what is known as a closed timelike curve. Timelike,
because the body never travels faster than light, and closed
because the rotating field brings the particle back into its own past
light cone. The net result — backward time travel (maybe). Weyl
thus realized, as far back as 1918, that matter not only warps
spacetime, but that rotating matter "drags" spacetime along
with it. Gödel's discovery only confirmed this effect.
But this is just science fiction, right? Many physicists today don't
think so. The dynamics of an object in free-fall within the dragged
spacetime of a massive spinning black hole are now well-known, and they
are bizarre. What is not known is what ultimately happens to the
object. Does it emerge from the black hole's ergosphere into another
place and time? Or does it eventually fall into the singularity, to be
crushed out of existence?
University of Connecticut physicist Ronald Mallett thinks that he might
have a clue as to how a table-top time-travel device could be
constructed using a circular rotating beam of laser light, which
theoretically produces dragged spacetime within its interior (to see
his short and very readable paper, go here.
).
Mallett with prototype device, circa 1960!
Mallett, whose father died at the age of 33 due to a heavy smoking
habit, decided at an early age to become a physicist so he could go
back in time and save his father. Mallett no longer believes this is
possible, but his fascination with the concept of time travel has
continued to this day unabated. So it is with many of us!
Since black holes result from the collapse of spinning stars and the
accretion of rotating matter, it is hardly an overstatement to say that
all black holes spin and so have angular momentum (neutron stars, the
closest cousins of black holes, can have measured spin rates of
hundreds and even thousands of revolutions per second). Therefore,
frame dragging (and all its associated odd phenomena) is the rule
rather than the exception in this wonderful, strange place that God
created for us.
Weyl
Letter with Autograph -- Posted by wostraub
on Tuesday, August 28 2007
If you're interested in
getting your own autograph of Hermann Weyl (I have several), have a
look at this offering on eBay.
The letter was sent to Artur Rosenthal, a mathematician at Heidelberg
University. Like other professors of Jewish descent, he was
summarily fired by the Nazis in 1933. By 1938 he was probably desperate
to get out of Germany. Weyl tried to get him a job at
Princeton. I don't know what became of him.
It's going for about $40 now, but my guess is it will top $100 by
auction's end. Good luck! [It sold for $158. Ouch.]
Expanding
Spacetime --
Posted by wostraub on Thursday,
August 23 2007
Some time ago I was
contacted by Johan Masreliez,
who has developed a theory of expanding spacetime somewhat along the
lines of what Hermann Weyl had proposed. But while Weyl assumed that
the metric tensor could be appended by a non-integrable 4-dimensional
scale factor, Masreliez' theory assumes that the metric involves a
factor that instead involves a global time factor alone.
General relativity is a classical theory, and one of its primary tenets
says that there can be no global time marker. Nevertheless,
cosmological models like the Robertson-Walker metric have
provided theoretically important descriptions of the behavior,
evolution and fate of the universe. So, I try to remain objective.
However, Masreliez' theory predicts that black holes do not exist.
While it is important to keep in mind that black holes have never been
directly observed, a universe devoid of these objects deviates so
radically from current cosmological thought that it really makes me
doubt that Masreliez is on the right track (also, I've been in love
with black holes for 40 years). Still, Masreliez' theory leads to some
pretty interesting things. So again, I try to remain open minded.
You can download Masreliez' book on his website. It's a fairly
straightforward read, and I recommend it.
Ralph
Alpher Dead at 86
-- Posted by wostraub on Friday,
August 17 2007
Ralph Alpher, the
George Washington University-trained physicist who was the first person
to fully understand the beginnings of the universe, died August 12 in
Austin, Texas.
Louise, his wife of 66 years, died in 2004.
When Alpher completed his PhD dissertation (actually his second, as the
first had to be abandoned) his advisor, the noted cosmologist George
Gamow, thought it would be fun to publish Alpher's results in the
prestigious journal Physical Review with the equally-notable
Hans Bethe as co-author (the names Alpher, Bethe and Gamow were a play
on the first three letters of the Greek alphabet). But the little game
backfired on Alpher, because the physics community mistakenly believed
that he had made only a small contribution to what turned out to be an
important paper.
Alpher's work proved that the early universe was composed of about one
helium atom for every ten hydrogen atoms, a result that holds up today.
Immediately after his dissertation paper was published, Alpher wrote
another paper proving that the Big Bang's fireball would leave a
background radiation having a temperature of about 5o
Kelvin.
But in the mid-1940s to mid-1950s, scientists could simply not believe
that the universe started out as a titanic explosion. Instead, they
preferred to believe in what was called the "steady-state"
theory, which held that the cosmos always existed (in spite of the
observed expansion of the universe). Alpher could not get any traction
on his Big Bang theories, so he left academia to work for General
Electric. He stayed there until his retirement in 1987.
In 1964, Arno Penzias and Robert Wilson of the Bell Telephone
Laboratory detected the background radiation that Alpher had predicted
twenty years earlier. The radiation, which was measured at 2.73o
K (still the modern value), established once and for all the validity
of the Big Bang theory and put the final nail in the coffin of the
steady-state theory.
But, incredibly, the Nobel Committee somehow overlooked Alpher's work
and awarded the 1978 Nobel Physics Prize to Penzias and Wilson, with
nary a mention of Alpher's ground-breaking theoretical research. Alpher
was understandably distraught at the oversight, and even suffered a
heart attack from the stress of fighting for recognition.
Alpher's is not the only hard-luck Nobel story, although more often
than not they involve women scientists (hooray for Curie, but you've
probably never heard of Lise Meitner or Rosalind Franklin, who both got
royally screwed by the male-dominated Nobel Committee).
But I would like to think that, right at this moment, God is busy
explaining everything about our wonderful universe to an awed and
overjoyed Alpher. As the apostle Paul had it, the world to come is far
better than the place we're in now.
Four
Neutrino Flavors?
-- Posted by wostraub on
Tuesday, July 17 2007
Hermann Weyl was
perhaps the first physicist to posit the existence of the neutrino. At
first it was only a mathematical prediction. In 1930, Pauli proposed the
neutrino in order to preserve mass-energy conservation. Twenty-five
years later, it was found experimentally. Still later, two more types
of neutrino were discovered following Weyl's death in 1955.
In the 1990s it was discovered that the three types of neutrino can
oscillate into one another or "mix." That is, a muon neutrino
could be "caught" as an electron neutrino, and so forth.
Because neutrinos are now known to have small but different masses,
they can exist as a superposition of three mass eigenstates.
That picture may now be changing. The July 2007 edition of Scientific
American includes a summary of the efforts by Fermilab researchers
and others to confirm very tentative evidence to date for a fourth
neutrino.
The Standard Model currently allows for only three -- the electron,
muon and tau -- all of which participate in the weak interaction. But
there is some leeway for a fourth species (dubbed the sterile
neutrino), with the provision that it not interact with the weak force.
If it exists, the sterile neutrino would interact only with gravity.
This scenario is in line with current string theory predictions in
which the sterile neutrino (like the graviton) can weave in and out of
multi-dimensional branes. One result of this mobility allows the
sterile neutrino to influence the flavor mixing of the other three,
which are supposedly bound to the four-dimensional
"braneworld" in which laboratory observations are made.
For a relatively simple explanation of neutrino mixing and how the
sterile neutrino might fit into the scheme of things, see this article
by Fermilab researcher B. Kayser.
Smolin
on String Theory
-- Posted by wostraub on Friday,
July 13 2007
I just finished
reading Lee Smolin’s The Trouble with PhysicsAmazon
Books, in which the renowned quantum physicist bewails the
impending failure of string theory. As a string-questioner myself
(actually, I don't get most of the theory's math at all), I think it's
a wonderful book!
Smolin is quick to point out that it’s not technically a theory,
because it cannot be tested. It’s more like a hunch. Meanwhile,
theoretical physics now finds itself in a desert, its greatest
achievements well behind it, with little more than string theory to
cling to.
And it all started with Hermann Weyl, to whom this often-annoying
website is devoted.
Smolin credits Weyl as the originator of the “unified
theory” craze that caught up Einstein, Pauli, Heisenberg,
Schrödinger and many others from 1918 until about the 1960s. String
theory then picked up where the old unified theories left off, and it
has been just as unsuccessful.
The so-called Standard Model of physics, known more affectionately as
SU(3)×SU(2)×U(1), reached its zenith in the 1980s and 1990s, when the
predicted weak-interaction particles Z0, W+ and W-
were discovered (1985) and the top quark was finally detected (1995).
Since then: very little, with the possible exception of the notion
(Smolin calls it a discovery) that neutrinos have mass. No wonder, he
notes, that the world’s smartest physicists are hitching their
stars to string theory.
Smolin, late of Yale and Pennsylvania State and now at the Perimeter
Institute, is no less an accomplished string theory expert himself. But
he sees little beyond the theory’s beautiful mathematics and the
allure of extra dimensions (seven at last count, not including the 3+1
of good old spacetime). Without experimental verification, it’s
really nothing more than a religion without even any Gospels to back it
up. He quotes physics Nobelist Gerard t’Hooft:
Imagine that I give
you a chair, while explaining that the legs are still missing, and that
the seat, back and armrests will perhaps be delivered soon. Whatever I
did give you, can I still call it a chair?
But Smolin
isn’t just complaining. He points out that there are other ideas
out there that might beat out strings as understandable and
experimentally verifiable unified theories: loop quantum gravity, spin
networks (see my post of earlier today) and various
spacetime-background-independent approaches to quantum gravity. So
there’s optimism to be had, but Smolin nevertheless regrets the
thousands of physicists and untold academic resources that are
currently being expended in the (possibly futile) search for strings.
Jesus Christ once said that there are many mansions in his
father’s house (John 14:2). I still think he was referring to the
many-worlds interpretation of quantum physics, in which there are an
infinite number of universes awaiting us after death. I don’t
personally see a need for many dimensions, and until string theory is
completely played out (hopefully in my lifetime), I will side with
Smolin.
Spin
Networks --
Posted by wostraub on Friday,
July 13 2007
For those of you who are
interested in an easy introduction to spin networks, John Baez has
posted a write-up by Roger Penrose on some of the simpler details.
You civil engineers out there who have done finite-element modeling
(structural dynamics, groundwater transport, pipe networks, etc.)
should find this easy going. Spin networks involve combinatorial
methods that preserve certain quantities at each vertex, although the
details are more complicated.
Here's a somewhat related problem for you engineers. If you can solve
it, you will become famous and probably very well-off.
Large finite-element grids involve very sparse admittance or coefficient
matrices whose components are based on the way the grid nodes are
numbered (sparse matrices have many zeros in them). Sparse matrices are
good, as they reduce computer storage requirements and computational
effort. All solution algorithms involve some method of inverting these
matrices in an efficient manner. If you take a square sparse matrix and
invert it, chances are it will no longer be sparse. But by simply
renumbering the grid, you can increase the sparseness of the inverted
matrix. The sparseness of the inverted matrix will always be equal to
or less than that of the coefficient matrix.
Example: the following graphs show the results of before-and-after
vertex renumbering. The renumbering increases the sparseness of the
inverted coefficient matrix by a factor of three (trust me):
Problem: develop an algorithm that produces the optimal renumbering
of the grid nodes such that the sparseness of the inverted matrix is as
large as possible.
Hint: Based on my playing around with the problem many years ago, the
solution likely involves combinatoric extremalization of the pure
number N = <x|A|x>,
where A is a square coefficient matrix (aij
= 1 if nodes i and j are connected, 0 otherwise) and x
is the numbering vector, which starts out as [1, 2, 3 ...]. Warning: discrete
extremalization is much more difficult than continuous
extremalization. You can't just take a derivative and set it equal to
zero!
Those of you who have investigated the "traveling
salesperson" problem will see a parallel here. Bell Labs has
worked on this problem for many years, as it's involved in how digital
communications are routed efficiently. Thousands of brilliant
scientists and mathematicians have not been able to come up with an
optimal solution. Indeed, it is not known whether such a solution even
exists. But maybe you can do it.
Oh, and yes, I have no life to speak of.
"We
do not know what death is ..." -- Hermann Weyl -- Posted by wostraub on Monday, July 2 2007
Last week, Peter Roquette,
Professor Emeritus of the University of Heidelberg, posted a
comprehensive and very moving description of the personal and
professional relationship between Hermann Weyl and Emmy Noether (whom
you can read about in my Weyl-Higgs write-up). Roquette, a
mathematician, has written extensively about the mathematical
correspondence between Noether and the German mathematician Helmut
Hasse. You can Google him if you want more information. Noether and Weyl Article
Included in Roquette's insightful article is the full text of Weyl's
funeral dedication to Noether on April 18, 1935, which contains
We do not know
what death is. But is it not comforting to think that our souls will
meet again after this life on Earth, and how your father’s soul
will greet you? Has any father found in his daughter a worthier
successor, great in her own right?
[Note: Noether's
father was himself an esteemed professor at the University of Erlangen,
and justifiably proud of his daughter's substantially greater
mathematical abilities.] It also includes Weyl's moving but fruitless
petition to have Noether retained as a professor in Germany in the
summer of 1933, when the Nazis summarily fired all scholars of Jewish
descent or heritage.
In coming to Princeton as a German emigre himself in late 1933, Weyl
selflessly endeavored to obtain a position for Noether at the Institute
for Advanced Study as well. This was denied (possibly because of the
school's antisemitic attitude), although she did find a position (at
reduced salary) at Bryn Mawr.
Science
and Religion, Again
-- Posted by wostraub on
Saturday, June 30 2007
I just finished
watching BookTV on C-SPAN2, which featured science writer Natalie
Angier talking about her new book The Canon: A Whirligig
Tour of the Beautiful Basics of Science. Angier is also a
recipient of the Pulitzer Prize, which she won in 1991 at the age of
33.
At one point she was asked about her interview with Dr. Francis S.
Collins, the born-again director of the Human Genome Project. The
question: how does Collins reconcile his Christian beliefs with his
scientific beliefs? Angier provided the answer: Collins sees no ambiguity
whatsoever. Angier then talks about how difficult it is for laypersons
to understand how one could be both faithful and scientifically-minded.
While the program was on, I happened to be finishing Veltman's book on
elementary particles (see my previous post). It suddenly dawned on me
that Young's two-slit experiment provides an ideal way of demonstrating
how faith and science not only can coexist, but also complement one
another.
If you pass light waves through a very small hole or slit in an otherwise
opaque barrier, the light spreads out on the other side, like the waves
that result when a stone is dropped into a still pool of water. If you
then pass light waves through two very closely-spaced slits, the waves
from each slit again spread out, but they interfere with each other.
The result is that the combined waves either reinforce themselves
(constructive interference) or cancel each other out (destructive
interference). All this is very straightforward and has been observed
countless times.
If
we now replace the beam of light with bullets fired at the slit, the
interference pattern disappears. That's because light is a wave, while
bullets are particles.
But now we fire a beam of electrons at the two slits. The interference
pattern reappears. That's because electrons are so small they can
exhibit wave-like properties. But now we fire the electrons one at a
time, say, one every day. Over a period of weeks and months, we see the
same interference pattern appearing. Somehow, a single electron is able
to interfere with itself! (We can do exactly the same thing with light,
where the intensity is reduced to one photon fired per week.) Again,
all this has been demonstrated countless times.
You may now ask, what if we follow one of the electrons to see which
slit it passes through? Maybe that will shed some light (no pun) on
this mystery. But if this is done, the interference pattern disappears.
It's as if Nature does not want us to really know what the hell is
going on.
Veltman asks: how are we to understand this? How can a single object
(like a photon or an electron) interfere with itself as it passes
through the slits? And why does the interference pattern disappear when
we try to determine which slit the particle passes through?
HIS ANSWER: The only thing that counts is what we observe. Until an
observation is made, we can obtain NO INFORMATION WHATSOEVER about what
is "really" going on.
And to me, this beautifully demonstrates the relationship between
science and religion. A true scientist can wonder about what is really
happening; she can formulate all kinds of theories involving
infinite-dimensional propagators and probability amplitudes, and maybe
some of what she proposes makes sense to other scientists, but she can
never really know what is going on. A true Christian looking at this
phenomenon can only say that this is the way God makes Nature behave.
Neither is more correct than the other in the absolute sense.
Scientists make observations and try to come up with explanations for
what they see. People of faith try to come up with explanations for
what they do not see. Science does not disprove the existence of God --
it's just that God is not relevant much of the time. Accounting theory
or mathematics does not need God, neither does the flow of electricity
or the interaction of elementary particles. Similarly, religion does
not disprove science. It may, however, try to get at WHY things are the
way they are. Science does not do that -- it always asks how, not why.
Collins is right -- there's no ambiguity at all. But there is a hell of
a lot of subjective, judgmental insanity going on in this world. Many
Christians scream "Evolution is anti-God!", while many
scientists yell "There is no need for a god!" In my opinion,
they're all wrong.
Did God create the world in six days? All right, what is a day?
Twenty-four hours? What was an hour when God forged the universe? Was
it 24 hours, or 24.000000001 hours? What the hell significance does an
hour mean to God anyway? It could have been 500 million years, the way
we measure it today. No one knows, because nobody alive today was there
to witness it.
Did you know that the Old Testament describes two different creation
events (Genesis 1 and Genesis 2)? When you track the descendants of
Adam through the Old Testament, how long did each ancestor live? Don't
know? Then you cannot postulate when Creation occurred. Science says
it's closer to 13.7 billion years ago, not 6,000. So where's the
problem?
As for science, you only have to ask one question to stop any
discussion about the existence of God. It is this -- WHY. That ends it,
because science can never answer that question.
The division between science and religion is purely political, designed
to drive the political parties in this country farther apart. The
winner discredits the loser, but of course everyone loses in the end.
But there is one important difference between these warring camps
today: even radically secular science will never demand that people be
burned at the stake for not believing in quantum mechanics, whereas
many people of faith today believe that President George W. Bush can
turns lies into truth.
Veltman
on Elementary Particles -- Posted by wostraub
on Wednesday, June 27 2007
A
non-scientifically-minded friend of mine recently pointed out to me
that, in accordance with Einstein's E = mc2, the
energy available to mankind must be nearly infinite. He reminded me of
the scene in Back to the Future where Doc Brown replenishes the
power source of his flying Delorean with a few banana peels and a shot
of stale beer, throwing in the beer can for good measure.
I had to explain to him that Brown's act violates all kinds of
conservation laws, not to mention the fact that nobody knows how to
convert the energy of ordinary matter into pure energy. Instead, I
asserted, Einstein's famous equation is useful mainly as a mass-energy
accounting tool, not a prescription for free energy from trash.
By far the best book I've seen to date that explains all this in a
straightforward and (mostly) non-mathematical manner is Martinus
Veltman's 2003 book Facts
and Mysteries in Elementary Particle Physics, admittedly
not the kind of book my friend would be picking up at Barnes &
Noble anytime soon. The 1999 Nobel Physics Laureate, Veltman
(curiously, his Christian name is the same as that of my late aunt's!)
is Professor Emeritus at the University of Michigan, although he
originally hails from Utrecht University in the Netherlands, where he
worked on weak-interaction physics. Veltman was the PhD advisor of
Gerardus t'Hooft (co-recipient of the 1999 Nobel with Veltman) who, as
a lowly Utrecht graduate student in 1971, proved that all gauge
theories are automatically renormalizable. This would have made Hermann
Weyl very proud, indeed.
I have one other book by Veltman, 1994's Diagrammatica: The
Path to Feynman Diagrams (paperback). Mathematically, it's a
readable, mid-level text that introduces canonical quantization from
first principles using creation/annihilation matrices whose properties
are so neat, they're actually fun. The Almighty Creator (who
undoubtedly knows these matrices intimately), is not only the greatest
physicist but is also entertainingly practical in the extreme.
Anyway, if you're interested in modern elementary physics and want the
best resource available on the subject at the layperson's level, you
can't go wrong with Veltman's book. It explains everything from quarks
and gluons to hadrons and their antiparticles on up, their interactions
and their conservation principles, along with brief but fascinating
sketches of many famous physicists. Equally enjoyable is Veltman's
rather strange and often hilarious use of the English language.
Krauss
on Extra Dimensions
-- Posted by wostraub on
Tuesday, June 26 2007
Case Western Reserve
University's Lawrence Krauss is a leading particle physicist and
cosmologist, and he has written a number of excellent books (including The
Physics of Star Trek, which I thought was rather silly, but that's
another story). His most recent book, Hiding in the Mirror,
discusses the subject of extra dimensions and why they hold so much
allure nowadays.
Krauss with friend
Krauss ends his book with Hermann Weyl's "Truth/Beauty"
quotation, and he graciously credits Weyl as the guy who essentially
started the entire extra-dimensions craze. Krauss seems to be not so
crazy himself about string theory, which proposes that we live in an
eleven-dimensional "membrane" world. Krauss feels that,
because string theory cannot (as yet) be demonstrated experimentally,
it is really no different than a religious belief. I do not know what
faith (if any) Krauss practices, but he is also a leading proponent of
reason over nonsense (he is especially critical of early creationism
and the right wing's continued attacks upon evolution), although that,
too, is another story.
It is true that Weyl's 1918 geometric gauge theory, like Einstein's
general relativity theory, involved only four dimensions, but his work
provided the stimulus for Theodor Kaluza's five-dimensional theory,
which was worked out in 1919. But all of these guys owed a tremendous
debt to the German mathematician Bernhard Riemann, who in the 1860s
developed the mathematical basis for all their work.
Krauss' book does not mention Riemann, a curious oversight in a book
dealing with extra dimensions. As perhaps the greatest mathematician of
the 19th century, Riemann was no stranger to multiple mathematical
dimensions. Riemannian geometry, perhaps Riemann's greatest
achievement, is the basis of modern geometrodynamics and, if Riemann
had lived a few more years, he might have trumped Einstein and
everybody else.
Sickly for most of his life, Riemann was born in 1826 and died of
tuberculosis at the tragically-young age of 39, not long after
developing his geometry. He was convinced that his was the "true
geometry of the world," and believed it could be used to describe
all physical phenomena. His initial efforts failed, but it was only
because Riemann was stuck in three dimensions. If he had only been
gifted with Einstein's foresight to view time as the fourth
dimension, the general theory of relativity (gravitation) would have
undoubtedly appeared around 1870, 45 years earlier than Einstein's opus
of November 1915.
Adieu
to Schrödinger --
Posted by wostraub on Wednesday,
May 23 2007
I finished Moore's
book on Schrödinger and found it to be a fascinating account of not
just Schrödinger's life and work but a glimpse of how the physicists of
his day struggled to make sense of the emerging quantum theory of the
mid-1920s.
It's interesting to note that Schrödinger initially wanted to believe
that the wave function Ψ was a purely real quantity, despite the
fact that it was embedded in his complex wave equation (actually, it's
a diffusion equation, but what the hell). It's also notable that
Hermann Weyl, Schrödinger's best friend, helped enormously with the
mathematics. In my opinion, it should have been called the
Schrödinger-Weyl equation.
In early 1927, Erwin and his wife Anny were invited to Cal Tech in
Pasadena. Anny found Pasadena "unbelievably beautiful, like a
great garden." The sentiment was echoed by Schrödinger, who loved
the Southern California climate. The great Dutch physicist Henrik
Antoon Lorentz (Einstein's idol) was also visiting at the time. It's
neat to think that these great scientists might very well have driven
down my street (Orange Grove Boulevard) exactly 80 years ago.
Schrödinger remarked to his host, the noted Cal Tech Nobel laureate
Robert Millikan, that he wished Pasadena were populated by Italians or
even Spaniards, not Americans, although he felt they were considerate
to a degree quite unknown in Germany at the time. This is
understandable, as Schrödinger, who had recently visited New York City,
hated the place and thought Americans to be uncultured.
Schrödinger:
Life & Thought
-- Posted by wostraub on
Tuesday, May 22 2007
I managed to find a
library copy of Walter Moore's Schrödinger: Life and Thought
and am in the process of reading it. Erwin Schrödinger was Hermann
Weyl's best friend (from their days together at the ETH in Zürich until Weyl's death in 1955), and I
thought this book would provide additional information on Weyl. Yes, it
did.
Moore relates the notoriously open relationship that the otherwise
devoted Schrödinger and Anny (his wife of 41 years) practiced, which
was due primarily to Erwin's predilection for extramarital affairs.
Schrödinger's intellectual abilities seems to have been matched only by
his libido, and he had many lovers, even into his old age. Anny herself
had her share of paramours, including Weyl (whom she called Peter):
Anny would find in
Hermann Weyl a lover to whom she was devoted body and soul, while
Weyl's wife Hella was infatuated with Paul Scherrer [another ETH physics professor].
This relationship was
confirmed in, of all things, a friendly letter from Anny to her husband
Erwin in 1936:
Even if the love
between Peter and me should sometime come to an end, I would always be
blessed that it had formerly existed, as I know that fate has given me the
greatest happiness that a person can ever be given.
But the best part of
the book (so far) is the story behind Schrödinger's famous wave
equation, and how he came across it late in 1925 (and even this story
involves an amorous romp between Erwin and an unknown former love in
Arosa, a secluded Alpine resort).
Amazingly, Erwin and Hermann remained best of friends until Weyl's
death in 1955. And when Schrödinger's heart finally stopped at age 73
on 4 January 1961, Anny was there to give him a farewell kiss. Go
figure.
If I find anything else interesting in the book, I'll report on it
later.
Biggest
Supernova Ever Seen
-- Posted by wostraub on
Tuesday, May 8 2007
A team of astronomers
from the University of California at Berkeley has discovered an
enormous supernova in the galaxy known as NGC 1260. It exploded in
September last year, producing the most massive outpouring of energy
ever witnessed. (Actually, because this galaxy is 240 million light
years away, the star blew up 240 million years ago.)
The supernova, designated as SN 2006gy, had an estimated energy output
of 1045 joules, enough to outshine the star's entire galaxy
of perhaps 200 billion stars. It's bigger than anything ever seen, and
its output has been remarkably persistent:
The pre-nova mass of SN 2006gy is estimated to have been about 150
solar masses. That's truly enormous, because stars that big are notoriously
unstable and have extremely short lives. But most supernovas blow off
only a fraction of their total mass into space, leaving a neutron star
or black hole behind. Scientists believe SN 2006gy blew up completely,
which would explain why the explosion's energy was so great.
Any chance of such a supernova occurring in our Milky Way? Well,
there's an unstable, 100-solar-mass star known as Eta Carinae about
7,500 light years away from us that scientists say will probably do the
same thing. Its light output would be so great that the supernova could
be seen during the day, but it would pose no hazard to life on Earth.
On the other hand, star explosions known as gamma-ray burstars
are far more dangerous; if one went off within several hundred light
years, most life on Earth would be extinguished (President George W.
Bush was recently overheard saying "We just gotta get one a them
things fer the Department of Defense").
Here's the Berkeley paper. It's about
10 pages long and somewhat technical, but very readable.
Eta Carinae underwent a colossal false nova event in 1843
which almost destroyed the star. It survived, but remains the best
candidate to date for a SN 2006gy-like explosion. The dumbbell-shaped
ejecta cloud streaming out of the region now dwarfs the central star
itself. Frightening.
Feynman's
Thesis -- Posted
by wostraub on Wednesday, May 2
2007
I finally got around
to reading Laurie Brown's book Feynman's
Thesis, which, to the best of my knowledge, is the only
publicly available version of Feynman's 1942 PhD dissertation. I was
astonished to find that Feynman's thesis, which details his discovery
of the path integral, is understandable, fun to read, and short -- incredibly,
the document's only 68 pages long. (Mine was the exact opposite -- at
225 pages, it was incomprehensible, boring, and long.)
I have long been fascinated by Feynman's idea, which represented an
entirely new approach to quantum mechanics. In fact, it represents
another quantum theory altogether.
Basically, Feynman said that a particle goes from Point A to Point B
along an infinite number of different paths, or "histories."
It can travel forward and backward in time, at any velocity, do loops, interact
with virtual particles, and cross the entire universe an infinite
number of times. Every path, no matter how improbable or illogical, is
just as important as any other path. Each path is assigned a
probability amplitude* that by itself says nothing. But when
you combine these amplitudes, you find that the infinite number of
paths available to the particle shrinks enormously. In classical
physics, the path that a particle settles into is the classical path --
a straight line in flat space, or a parabolic arc in the presence of
gravity.
Several years ago I tried to explain this in my write-up Introduction to Quantum Field Theory.
I wrote the path integral part off the top of my head, and today I was
pleased to find that it was remarkably similar to Feynman's treatment
in his dissertation.
Now if only I could understand all that Feynman did in the 46 years
following his Princeton thesis!
* The probability amplitude of an event is a complex number
whose norm (its "square") is a real number. The physicist
Nick Herbert describes things this way: the wave function Ψ
is a probability amplitude, also called a "possibility,"
while its square Ψ*Ψ is a real number,
the "probability."
The
Most Beautiful Thought -- Posted by wostraub
on Saturday, April 28 2007
Right after his
discovery of special relativity in 1905, Einstein was looking for a
more general application of his theory -- one that included
gravitation.
I think it was in 1908 or thereabouts that he had what he later
described as the most beautiful thought of his life: if a person were
to to fall off the roof of her house, she would not feel her own weight
during the fall. Einstein instantly realized that the phenomenon known
as gravity could be transformed away by a suitable change of
coordinates, and he began to look for a description of relativity that
was independent of any particular coordinate system. This led him
ultimately to his 1915 theory of general relativity, which is cast in
the coordinate-invariant language of tensor calculus.
I was instantly reminded of this little story of Einstein's when I read
about Stephen Hawking's recent
experience with weightlessness. The 65-year-old Lucasian
Professor of Mathematics at Cambridge University boarded the Vomit
Comet and undertook half a dozen parabolic "plunges," each of
which rendered him weightless and floating for 20 to 25 seconds. He
remarked later that he greatly enjoyed a brief chance to escape his
wheel chair and experience Einstein's beautiful thought first hand.
Although I believe that purely recreational flight (like billionaires
paying millions to go into orbit) is a ludicrous waste of resources,
I'm happy for the guy (and I'm sure Einstein was with him in spirit).
Weyl's
1929 Paper --
Posted by wostraub on Tuesday,
April 24 2007
I once remarked that
I planned to review Weyl's 1929 paper "Electron and
Gravitation," which formally presented Weyl's gauge idea in the context
of the then still-emerging quantum theory. While I've always found
Weyl's physics to be straightforward, his mathematics tends to be
rather obtuse and difficult to follow (at least for me). Complicating
the matter is the fact that Weyl's notation is unfamiliar to many
physicists (for example, Weyl expresses the tetrad as ea(β)
rather than the purely tensorial index form eaβ).
Maybe this is no big deal, but I have a hard time following stuff when
the notation is odd.
Lochlainn O'Raifeartaigh's excellent 1997 book The
Dawning of Gauge Theory includes a translation and
detailed clarification of Weyl's paper (with modernized notation), but
it's still a tough read.
Prof. Wulf
Rossmann of the University of Ottawa recently contacted me on a
different matter but then put me onto his own take of Weyl's paper. He
sticks with Weyl's tetrad notation but to his credit clarifies Weyl's
paper to a greater extent than O'Raifeartaigh. The interested reader
will definitely want to visit Rossmann's website (which includes his
book on differential geometry in downloadable pdf format, along with
other online papers).
Rossmann also points out a reference in Weyl's paper that has always
puzzled me. In the the paper's first section, Weyl notes that his
2-component spinor ψ is unable to accommodate left-right
parity; he correctly surmises that parity would therefore require
another, independent 2-component spinor (Weyl even suggests that this
spinor describes the proton). Weyl cryptically notes that he will
address this issue in a "Part II," but he never mentions it
again. Rossmann believes that Weyl never wrote Part II because
Anderson's 1932 discovery of the positron (not to mention Chadwick's
discovery of the neutron in the same year) compromised Weyl's ψ-connection
in its relationship with the Weyl current j μ=ψ*σ μψ
(σi are the Pauli matrices; σ0
is the 2×2 unit matrix). Thus, Weyl's hope for a theory of
everything (which in those days was just gravity and
electrodynamics) was quashed for good.
Finally, Rossmann offers the following quote from Weyl's book Space-Time-Matter,
which is all too true (but gives non-mathematicians like me little
solace):
Many will be
horrified by the flood of formulas and indices which here drown the
main idea of differential geometry (in spite of the author's honest
effort for conceptual clarity). It is certainly regrettable that we
have to enter into purely formal matters in such detail and give them
so much space; but this cannot be avoided. Just as we have to spend
laborious hours learning language and writing to freely express our
thoughts, so the only way that we can lessen the burden of formulas
here is to master the tool of tensor analysis to such a degree that we
can turn to the real problems that concern us without being bothered by
formal matters.
Weyl's
Pedestal Shaken a Bit -- Posted by wostraub
on Tuesday, April 17 2007
In 1970 I took three
courses in physical chemistry at university. The book we used was Walter
Moore's text, appropriately entitled Physical Chemistry. Now a
classic, it was, and still is, a tough book, especially the chapter on
quantum chemistry. As I recall, we undergrads didn't like Moore very
much.
Over thirty years later, in 2001, Moore wrote a biography of the great
Austrian physicist Erwin Schödinger called Schrödinger: Life
and Thought, which was reviewed
for the New York Times by Richard Teresi, the author of The
Three-Pound Universe. Here is an excerpt from that review:
Schrödinger's wave
equation, published only a few weeks later, was immediately accepted as
"a mathematical tool of unprecedented power in dealing with
problems of the structure of matter," according to Mr. Moore. By
1960, more than 100,000 scientific papers had appeared based on the
application of the equation. Schrödinger lavishly thanked his physicist
friend Hermann Weyl for his help with the mathematics. (He was
perhaps indebted to Weyl for an even greater favor: Weyl regularly
bedded down Schrödinger's wife, Anny, so that Schrödinger was free to
seek elsewhere the erotic inspiration he needed for his work.)
Ouch. I'm not a
prude, but this aspect of Weyl's personal life troubles me. I have read
in numerous places that post-World War I Germany was sexually
liberated, and I already knew that Einstein had more than a few sexual
skeletons in his closet, but this hits close to home.
I have not yet read Moore's Schrödinger book, primarily because a) I
don't want to pay Amazon
$50 for the thing; b) it's not available from my library's interlibrary
loan program; and c) I'd already had enough grief from Moore almost 40
years ago. But if I can lay my hands on a copy I'll you all know what I
think of it -- and whether my opinion of Weyl changes any as a result.
Arrhenius
and Climate Change --
Posted by wostraub on Monday,
April 9 2007
Svante Arrhenius was a
Swedish chemist who, around 1895, was the first to quantify the
relationship between chemical reaction rates and temperature. He won
the Nobel Prize in Chemistry in 1903 for his work on electrolyte
theory.
Every undergraduate chemistry major learns how to derive Arrhenius'
rate equation, but what most don't realize (as I didn't realize at the
time) was that Arrhenius was the world's very first climate modeler. In
1894 he derived a remarkably accurate relationship between atmospheric
carbon dioxide levels and global temperatures. Using only a slide rule,
he calculated that a doubling of CO2 concentrations would
raise the Earth's average temperature by 9.9oF. By
comparison, today's modern supercomputers and vastly more accurate
climate models predict an increase of 10.4oF.
Arrhenius' story is recounted by environmental writer and journalist
Fred Pearce in his new book With
Speed and Violence: Why Scientists Fear Tipping Points
in Climate Change. An erstwhile skeptic of doomsday climate-change
scenarios, Pearce looks at all the evidence from all the angles, and
comes up with a prediction: we're all in very big trouble.
Even Arrhenius could not have foreseen the day when humans would be
pumping out 8.2 billion tons of CO2 into the atmosphere
annually, an amount far in excess of the planet's ability to absorb
without global climatic consequence.
From CO2 buildup and the breakdown of the Atlantic Conveyor
to deforestation and the unavoidable release of tens to hundreds of
billions of tons of frozen Siberian methane, Pearce paints a bleak
picture for 21st century Earth and its inhabitants.
While reading the book, I was at once struck by the words of Chris
Hedges in a recent edition of New Statesman,
where he notes that the real motivation of today's fundamentalist
Christians is not religiosity but despair:
... The danger of
this theology of despair is that it says that nothing in the world is
worth saving. It rejoices in cataclysmic destruction. It welcomes the
frightening advance of global warming, the spiraling wars and
violence in the Middle East and the poverty and neglect that have
blighted American urban and rural landscapes as encouraging signs that
the end of the world is close. Those who cling to this magical belief,
which is a bizarre form of spiritual Darwinism, will be raptured
upwards while the rest of us will be tormented with horrors by a
warrior Christ and finally extinguished. The obsession with apocalyptic
violence is an obsession with revenge. It is what the world, and we who
still believe it is worth saving, deserve.
If true, then may God
forgive us all.
Hermann
Weyl in Göttingen
-- Posted by wostraub on Monday,
April 2 2007
Here are some photos
of Weyl talking at two separate colloquia taken in the early 1930s. The
original caption on the first photo indicates that the lecture hall was
filled to capacity, as the students at Göttingen did not know how much longer
Weyl would be staying in Nazi Germany (Weyl's wife was Jewish, which
jeopardized Weyl's entire family; they ultimately emigrated to America
in November 1933). The second shows Weyl with the great German
mathematician Richard Courant (far left).
Relativity
for the Masses --
Posted by wostraub on Saturday,
March 17 2007
The act of Taylor
& Wheeler (MIT's Edwin F. Taylor and Princeton's John A. Wheeler,
that is) has produced two books that you need to read if you want to
learn special and general relativity quickly.
The first is 1992's Spacetime Physics, a 300-page fun read that
covers pretty much everything on Einstein's special relativity. The
book's side bars feature two iconic characters (Rodin's The Thinker
and a wise-cracking black crow) who help guide the reader through
special relativity's often confusing concepts (these guys are much like
Simplicio and Sagredo from Galileo's Dialogues).
This book will also show you how to do some amazing calculations using
only the flat-space metric ds2 = c2dt2
- dx2. For example, if you want to go to the Andromeda
Galaxy in one year, all you have to do is build a spaceship capable of
traveling at 0.999999999999875 times the speed of light*.
Of course, your friends on Earth will be 2 million years older when you
get there, but you can always make new friends in Andromeda. Also,
President Bush will almost certainly be dead by the time you arrive.
Break out the champagne!
The second book is 2000's Exploring Black Holes: An Introduction to
General Relativity. It follows the same format but deals with
general relativity, the theory of warped spacetime and gravitation. The
book focuses primarily on simplified presentations of the Schwarzschild
and Kerr metrics (which respectively describe static and rotating black
holes), which are really all you need to know about gravity. Thinker
and Crow are back again to make sense of the mathematics, which
requires a knowledge of elementary calculus.
Wheeler, who will be 96 this year, is one of the few still living great
physicists from the days of Einstein, Dirac, Wigner, von Neumann and
Pauli. He knew them all personally, and he also knew Weyl well (you can
read Wheeler's tribute to Weyl elsewhere on this site). Wheeler coined
the term black hole in December 1967. Why he never won a Nobel
Prize is a great mystery to many people.
Interesting tidbit: Wheeler graduated from Johns Hopkins University in
1933 with a PhD in physics. And that's all he got -- he skipped getting
his BS and MS. Talk about being focused!
* The energy needed to bring every pound of your
spaceship up to this speed is equivalent to approximately one billion
Hiroshima-size atom bombs.
The
Natural Gauge of the World -- Posted by wostraub
on Friday, March 16 2007
Sometime ago I wrote about
Eddington and his unified field theory of 1921, the one that Weyl
called "not worthy of discussion." But it was Eddington who
came up with the phrase "natural gauge of the world," and in
was in the spirit of Weyl's 1918 theory that he proposed it.
In Eddington's theory the Ricci tensor Rμν,
like Weyl's version, is constructed from a symmetric metric gμν
and affine connection Γλμν.
He then separates the Ricci tensor into its symmetric and antisymmetric
components; the symmetric part is then made proportional to the metric
tensor using a gauge scalar that, for all intents and purposes, is the
cosmological constant. This gauge, asserted Eddington, represents the
natural gauge of the world.
The great Austrian physicist and all-round curmudgeon Wolfgang Pauli
was appalled. He denounced Eddington's theory as having "no
significance to physics" and expressed his resentment of having a
mathematician poke his nose into the realm of the physicists (actually,
Eddington was both), a criticism that Pauli later directed at Weyl
regarding the latter's application of the gauge concept to quantum
mechanics. But Weyl won his argument, with Pauli apologizing and
admitting that Weyl had been right all along.
Still, Eddington raised an important question: if the world permits (or
demands) that metric spacetime be conformally rescalable from point to
point, then what is the nature and consequence of that symmetry?
Indeed, the British mathematical physicist Roger Penrose is very much
enamored of conformal invariance, and he asserts that the Weyl
conformal tensor Cλαμν
(which lies at the heart of the Weyl Curvature Hypothesis, or
WCH) is essentially responsible for entropy and the assumed asymmetry
of the arrow of time. Penrose even goes so far as to say that the WCH
must be an essential element of a successful quantum gravity theory,
which itself must be time asymmetric. This results from the assertion
that the Big Bang was a topologically distinct event in the history of
the universe -- the Weyl curvature tensor was identically zero at the
time, whereas it is positive now and will remain positive (or even
become infinite) regardless of whether the universe continues to expand
forever or eventually falls back on itself in a Big Crunch.
You can learn a little more about Weyl's conformal tensor (and how to
derive it) in my write-up on the menu to the left.
Hermann
Weyl -- The Centenary Lectures -- Posted by wostraub
on Saturday, March 10 2007
I just finished
reading Hermann Weyl, 1885-1985: The Centenary Lectures, three
talks that were given by C.N. Yang, R. Penrose and A. Borel on the
100th anniversary of Weyl's birth.
I've hunted all over for this book. Caltech didn't have it, or
Berkeley, or UCLA, or Stanford; it finally turned up at Cal State
Fullerton!
Anyway, it's interesting because it includes a full bibliography of
Weyl's works, which total 167 scientific and mathematical papers, 17
books, and a dozen or so lecture notes. Also interesting is the fact
that he published only a handful of physics papers after his move to
the Institute for Advanced Study at Princeton in 1933, the year he left
Germany (by his own admission, Weyl's interests changed as a result of
his emigration).
The book includes transcripts of some of the speeches that were made at
the Centenary Dinner held on October 24, 1985 at the Swiss Federal
Technical Institute (the university where Weyl taught from 1913 to
1930). I was struck by the depth and breadth of Weyl's literary, poetic
and philosophical interests, subjects that he knew intimately from the
likes of Democritus, Leibniz, Kant, Mann, T.S. Eliot, Husserl, Russell,
Kierkegaard, Nietzsche and Heidegger. How the guy ever had time to read
all this stuff, while maintaining a reputation as one of the world's
leading mathematical physicists, is simply beyond me.
Best of all, the book includes the speech given by Weyl's son Michael,
also a PhD, whom I've been trying to locate for some time now. It is a
touching and heartfelt reminiscence of a son who fully appreciated
having a father who was not only a "mathematician-father with the
soul of a poet" but a truly learned man who passed on his passions
to Michael and his mathematician brother, Dr. Joachim Weyl.
In his speech, Michael included this poem by the minor poet Anna
Wickham (1884-1947):
God, Thou great
symmetry,
Who put a biting lust in me
From whence my sorrows spring,
For all the frittered days
That I have spent in shapeless ways
Give me one perfect thing.
Hermann Weyl included
this poem in his last book, Symmetry, in which he remarks that
the sphere in space represents true perfection -- so perfect, in fact,
that it inspires not only awed admiration but sorrowful longing as
well, because it is a reflection of the perfect symmetry and
unattainable perfection that is God himself.
Weyl's
Gauge Factor, Again
-- Posted by wostraub on Monday,
February 26 2007
Several people have
written me asking how Weyl’s geometry might be modified using the
nonintegrable gauge factor that I mentioned in my December 19 post.
There I suggested that the line element ds2 could
be made gauge invariant (or conformally invariant) via a
“phased” metric tensor:
gμν → exp[k∫φλdxλ]
gμν
where k is a suitable constant. In addition to the line
element, all tensor quantities constructed from the new metric (the
metric determinant, the Riemann-Christoffel tensor and its
contractions, the Christoffel symbols, etc.) would then be automatically
gauge invariant, as would all quantities raised and lowered using the
new metric.
Well, I had never considered this possibility, so I did a few
calculations to see if it leads to anything interesting. For one thing,
we can now define an action Lagrangian that is linear in the Ricci
scalar density to get the free-space field equations:
S = ∫√(-g) R d4x
where the Ricci scalar R is constructed solely from the new
metric. Here we are on familiar ground again, as the above quantity is
the old Einstein-Hilbert gravitational action we all know and love.
Thus, we neatly kill off the two objections Einstein held against
Weyl’s theory: a non-gauge-invariant ds, and a
fourth-order action Lagrangian.
However, if we try to append the Maxwell action terms Fμν
Fμν and sμ φμ
(where sμ is the electromagnetic source
four-vector) to the above Lagrangian density, we immediately run into a
problem: sμ φμ is not
gauge invariant! Of course, it’s not gauge invariant in any other
theory, either, but here it’s particularly problematic. Making
matters worse is the fact that the Weyl vector φμ
does not exhibit a true gauge weight (instead, it's a gradient, making
an integration by parts necessary, which really messes things up).
This brings up an issue I’ve thought about for a long time: Just
what the hell is the source vector, anyway? Classically, it’s
just
sμ = ρ(x) dxμ/ds
where ρ is the electromagnetic 3-density. It seems like
the only way to make this quantity gauge invariant is to consider its
interaction with φμ and some quantum
field, along the lines of Ψ*sμΨ,
etc., and then impose gauge conditions on the wave function.
I'll think about it, but I don't believe it goes anywhere. Suggestions?
Squid
Memories --
Posted by wostraub on Thursday,
February 22 2007
Is it my imagination,
or are giant squids (not Superconducting Quantum Interference
Devices, but the scary ones with tentacles) showing up more
frequently nowadays?
New Zealand fishermen looking for fish in Antarctic waters accidentally
hooked a Colossal squid weighing almost 1,000 pounds and
measuring over 30 feet in length. Article
The colossal squid, known even by elementary school children as Mesonychoteuthis
hamiltoni (just kidding), is the larger (!) cousin of the more
familiar giant squid (Architeuthis), which may grow to longer
lengths but is rather more slender.
I've had a life-long fascination with these things. When I was five, my
father took me to see Disney's 20,000 Leagues Under the Sea
(that was in 1954), and several years later my older sister took me to
see It Came From Beneath the Sea. By then I was hooked, so to
speak. Disneyland used to have a full-sized model of a giant squid in
its 20,000 Leagues Exhibit in Tomorrowland. It was so realistic that as
a child I had a really hard time going in there:
In the 1980s, while scuba diving in extremely murky water off the
Coronado Islands, some enormous, shadowy thing came up behind me. I
turned, and as I did it quickly swam off, leaving me spinning head over
heels in the backwash. The ascent back to the surface (I had been down
about 100 feet) seemed to take forever. I never really got a look at
it, but on the boat the divemaster told me it was only a harmless grey
whale that had been seen swimming nearby. Nevertheless, that was the
last dive I made that day.
Lorentz
Symmetry -- Still Asking -- Posted by wostraub
on Friday, February 16 2007
It was Hermann Weyl
who showed that quantum mechanical gauge invariance is the continuous
symmetry responsible for the conservation of electric charge. Lorentz
invariance (invariance of the Lagrangian with respect to Lorentz transformations)
is also a continuous symmetry, so what conservation principle does it
represent?
I've addressed this problem before, but nobody was able to help me with
it. Baez
has been asked this same problem, but his answer is less than
illuminating.
In his excellent book The Road to Reality: A Complete
Guide to the Laws of the Universe, British mathematical physicist
Roger Penrose provides the answer. In non-relativistic mechanics, the
quantity
N = pt - mx
where t is time, p is the 3-momentum and x
is the position vector, is (obviously) invariant with respect to time.
Penrose notes that Lorentz invariance is responsible for making the
center of mass of a particle (or that of a collection of particles)
move in a straight line, with velocity p/m.
Pretty simple, isn't it? But I'll be damned if I know how to derive it!
(short of using the Lorentz generators, as this
guy does it). Penrose doesn't derive it either, but only says
that Lorentz symmetry is a tad less common than rotational symmetry.
Well, that's a big help.
Penrose obviously doesn't take into account idiotic readers like
myself.
Juliet
or Esmerelda? --
Posted by wostraub on Wednesday,
February 7 2007
Unlike her happier
fate in motion pictures, the gypsy Esmerelda in Victor Hugo's classic
novel The Hunchback of Notre Dame dies by hanging. Her lovelorn
admirer, the hideous hunchback Quasimodo, dispatches the corrupt Frollo
but is unable to save the love of his life. Heartbroken, he disappears.
Years later, grave diggers accidentally unearth the skeleton of
Esmerelda, which is inexplicably embraced by that of a grossly deformed
man. [And] when they tried to detach the skeleton which he held in
his embrace, it fell to dust.
Cut to February 2007. Archaeologists working in Mantua, Italy (about 25
miles south of Verona) uncover the skeletons of two Neolithic people
embraced in death. The remains, those of a young man and a young woman,
are estimated to be from 5,000 to 6,000 years old. Neolithic burials
nearly always involve only a single skeleton. Evidently, there was
something very special about these two people from long ago. Sadly,
their story is lost to us. Article
Coincidentally, Shakespeare placed his Romeo and Juliet in
Verona, Italy. The ending to that story wasn't very pleasant, either.
Something about a happy dagger that finds its sheath ...
Touching.
Famous
Papers -- Posted
by wostraub on Wednesday,
January 31 2007
The website Trivial Anomaly provides links
to a dozen or so sites where you can read or download seminal papers of
famous scientists. Want to see a translation of Einstein's original
1915 paper on the general theory of relativity? How about Schrödinger's
1926 paper announcing his discovery of wave mechanics? It's pretty neat
stuff.
I'm also pleased that it includes my write-up of Weyl's 1918 gauge
theory, perhaps because it's more detailed than the paper Weyl
originally wrote (and because you don't have to know German to read
it).
Hermann
Weyl in Exile --
Posted by wostraub on Wednesday,
January 24 2007
I just finished
reading Forced Migration and Scientific Change: Emigre
German-Speaking Scientists and Scholars After 1933 (1996), a collection
of articles edited by Mitchell Ash and Alfons Söllner. Of particular
interest is the chapter Physics, Life and Contingency: Born,
Schrödinger and Weyl in Exile by Sküli Sigurdsson, whose 1991 PhD
dissertation on Hermann Weyl I'm still trying to run down.
The book is not so much an overview of how emigrating German and
Austrian scientists dealt with Hitler's rise to power in 1933 but a
brief history of how their views on science, mathematics and philosophy
were altered in the years immediately following the end of World War I,
up to the time they left Germany.
Sigurdsson's article provided me with a little more information on
Weyl's state of mind in the years 1918-1933 than I'd seen previously.
For example, his decision to accept the mathematics chair in 1930 at
Göttingen when the great David Hilbert retired was not an easy one. He
seems to have accepted it more out of nationalistic pride than for any
other reason, believing that he needed to help Germany maintain its
"thought collective" and promote its tradition of
highest-quality science. Nevertheless, he announced his resignation in
October 1933 after becoming depressed and disillusioned with the Nazis,
the overall political and economic climate of Germany, and the
resulting restrictions on scientific inquiry.
During his years at Göttingen, Weyl's productivity had waned
considerably and he was dissatisfied with the quality of science at the
school. At his previous post at the Swiss Technical University in
Zürich (where he was Mathematics Chair from 1913 to 1930), Weyl was the
highest paid professor. His salary was increased at Göttingen, but was
soon cut because of the school's rapidly deteriorating finances, the
result of Nazi-imposed state cutbacks in higher (and mostly
theoretical) education.
In January 1933 Weyl received an offer from Princeton's new Institute
for Advanced Study. But he was so depressed that he could not muster
the strength to make the decision to accept (he seems to have had
difficulty throughout his life making life-altering decisions, an
observation that was later confirmed by the great Göttingen
mathematican Richard Courant). However, Weyl's wife was Jewish, which
placed both her and their two sons in jeopardy with the Nazis. This
forced Weyl to accept Princeton's invitation, and the family left for
America in November 1933.
For Weyl, Born and Schrödinger, their forced emigrations (Born was
Jewish and thus barred from teaching, while Schrödinger quit in protest
over Born's firing; both men emigrated to England) brought about
significant changes in their attitudes and philosophies regarding
science and mathematics. Weyl retreated more and more into pure
mathematics and pretty much abandoned his earlier interest in
mathematical physics, particularly unified field theory. His book Classical
Groups came out in 1939, while his earlier interest in physics and
philosophy waned. And when he finally returned to Europe after his
retirement in 1952, Weyl went to Zürich, not his beloved Germany.
Sigurdsson's article is rather dry and humorless, but there is one
funny anecdote worth repeating. Weyl suffered from asthma and hay
fever, and Sigurdsson notes that Weyl's decision to go to the Institute
for Advanced Study was compromised by the fact that he could not get
affordable health insurance in America!
Plus ça change, plus c'est la même chose ...
Eddington -- Posted by wostraub on Tuesday, January 23
2007
Earlier I remarked that
God cannot create a new integer between the numbers 1 and 10. Here's a
little story about how one man tried to do essentially the same thing.
Sir Arthur Stanley Eddington (1882-1944) was a British astrophysicist
who, like Hermann Weyl, tried to develop a unified theory of
gravitation, electromagnetism and quantum mechanics. His 1921 book The
Mathematical Theory of Relativity (a copy of which I happen to
own) praises the work of Weyl, whose ideas Eddington used to advance his
own theory. But the physics community at the time roundly criticized
Eddington's ideas; Weyl himself even went so far as to call them
"not worthy of discussion" (undiskutierbar) in 1923.
But it was also Eddington, who, on a solar eclipse expedition in 1919,
took photographs of the sun and nearby stars and verified, rather
sloppily, Einstein's prediction that gravity can bend starlight. Thus
it was Eddington who made Einstein into an overnight scientific
superstar.
Anyway, as brilliant as he occasionally was, Eddington made one famous
goof. There happens to be a fundamental, dimensionless constant in
quantum physics known as the fine structure constant, which is
defined as
2πe2/hc = ≈ 1/137
where e is the electron charge, h is Planck's
constant, and c is the speed of light (the fact that this
constant is very nearly the reciprocal of the prime number 137 has
profoundly disturbed physicists for over 80 years). But in Eddington's
day, uncertainties in the values of Planck's constant and the
electronic charge made this number closer to 136. With characteristic
aplomb, Eddington set out to prove that it was exactly the
integer 136.
By considering the magnitudes of certain quantities in an abstract
phase space, Eddington came up with the number function
ƒ(n) = ½ n2(n2 + 1)
and, using some kind of reasoning, Eddington believed that ƒ(4)
= 136 was the fine structure constant (Eddington used a similar
argument to "prove" that the ratio of proton mass to electron
mass was also an integer, 1836).
Only several years later, it was determined that the fine structure
constant was actually closer to 137. Not to be outdone, Eddington,
admitting to an earlier algebraic oversight, revised the above formula
by adding +1 to the right hand side, thus recovering the correct value
for the constant.
But the world's physicists were not to be taken as fools. They
renounced Eddington's preposterous theory and, in mild rebuke, jokingly
dubbed him "Sir Arthur Stanley Adding One."
Note: Interestingly, the late, great German Nobel laureate physicist
Max Born (who happened to be Olivia Newton-John's grandfather!) noticed
that Eddington's formula reproduced two numbers from the New Testament
Book of Revelation, Chapter 13:
And I saw a beast
coming out of the sea having ƒ(2) = 10 horns ... [and]
his number is ƒ(6) = 666.
I feel fairly certain
that God did not use Eddington's formula when he inspired John to write
Revelation!
PS: Wolfgang Pauli (Nobel physics prize, 1945) was also fascinated by
the fine structure constant, and he devoted much time and thought to
its provenance. He passed away from cancer in 1958, and the number of
the hospital room where he died was ... 137. Good one, God!
Twenty
Eighty -- Posted
by wostraub on Monday, January
22 2007
My older son's
girlfriend loaned me a copy of James Surowieki's book The
Wisdom of Crowds. It's really interesting -- it pretty much
destroys the idea that irrational mob rule is the norm, and shows how
crowds of people may have differing points of view but, when the
average is taken, it tends to be pretty close to the truth. The book's
one caveat is that a crowd must have a fairly firm grasp of reality,
otherwise mob rule does indeed take over, with disastrous results.
You've probably heard about the 20/80 rule: 20% of the workforce does
80% of the work; 20% of people are difficult, while you can get along
with the other 80%; 20% of the population is outright irrational, while
80% seem to have some grasp of what's going on, etc.
Well, that seems to apply only to the rest of the world. Here in
America, we have the 33/67 rule: 33% of all Americans are out of their
friggin' minds.
The most recent polls
show that Bush's approval rating is now at 33%, the lowest for a
sitting president since "I am not a crook" Richard Milhous
Nixon occupied the White House. This is awful, but the flip side of the
coin is that 33% of Americans still think Bush is doing a great job.
I know such people. While perhaps not certifiably insane, they all seem
to have the mindset for nonsensical and/or dogmatic thinking. They are
also very suspicious of things they do not want to believe, while
leaving themselves open to outright falsehoods that they do want to
believe. And they tend to believe what they are told to believe.
I once asked one such person (with two M.S. degrees in engineering,
yet) if she believed it was possible for God to create a new integer
between the numbers 1 and 10, or if scientists had somehow overlooked
an undiscovered chemical element between sodium and magnesium in the
periodic table. "Yes, of course," she replied, "because
sin has blinded us from the truth." How does one begin to argue
with such nonsense?
The trouble is, I like a lot of these folks. Most are decent people,
and share the same Christian values that I hold to. But many have
allowed their values to become warped by political opportunists and
liars.
If Bush's popularity was 20%, he would undoubtedly be exposed as the
monster he truly is. Impeachment and prosecution as a war criminal
would probably follow. But at 33% he can hang on.
20/80 works, but 33/67 does not.
America cannot survive when 33% of its people are crazy. And I fear
that neither can the rest of the world.
Weyl
and von Neumann
-- Posted by wostraub on
Saturday, January 13 2007
There's a story that Hermann
Weyl, when talking about his work at a conference or lecture hall,
would become extremely agitated whenever colleague John von Neumann was
in the audience. His nervousness was presumably due to the fact that
von Neumann was widely viewed as a genius, and Weyl was afraid he'd
make a fool of himself.
A better word would be "respectful," because in actuality the
two men were friends as well as colleagues. And while it is quite true
that von Neumann was a mathematical genius, his brilliance extended into
physics, economics and linguistics as well. For example, at the age of
six he was fluent in Greek (along with his native Hungarian), and could
divide two 8-digit numbers in his head within seconds. Later, von
Neumann did pioneering work in computer science, and today is known as
the father of the digital computer (see my December 12 post).
There is a famous story involving von Neumann, apparently even true,
that he was approached by the hostess of a party he was attending and
given the following puzzle to solve:
Two bicyclists on a
road are 100 miles apart. At a predetermined time they begin pedaling
toward each other, each with a uniform speed of 10 mph. At the moment
they start out, a fly sitting on the wheel of one of the bicycles
starts flying toward the other bicycle at a speed of 20 mph. Upon
reaching the other bicycle, it instantaneously turns around and starts
flying back to the first bicycle. It does this repeatedly until the
bicycles meet in the middle of the road, squishing the fly between the
tires. How many miles does the fly travel?
[This story is so old
that I am almost ashamed to repeat it.] There are two ways to solve the
problem, but one way is immediate: the bicyclists meet at the midpoint
after 5 hours of pedaling. The fly has been flying constantly during
this time, so it flies a total of 5×20 = 100 miles. The second method
involves calculating the infinite series L = 100/3 ∑ (2/3)n,
where the sum is taken from n = 0 to n = ∞.
Again, L = 100 miles.
At the party, when asked for the answer, von Neumann instantly said
"100 miles." The hostess smiled and said, "Oh darn, you
know the trick." To which von Neumann replied, "What trick? I
got it by doing the infinite series."
Herman
Weyl and Yang-Mills Theory -- Posted by wostraub
on Thursday, January 11 2007
In his great 1929
book The Theory of Groups and Quantum Mechanics, Hermann Weyl
jokingly remarked that It is rumored that the ‘group
pest’ is gradually being cut out of quantum mechanics. Weyl
was referring to objections that many physicists were voicing at the
time about the use of group theory (which was viewed as pure
mathematics) in the then-emerging field of quantum mechanics. Of
course, as both a mathematician and physicist Weyl could already see
the importance of group theory in quantum physics, and his seminal
paper Electron and Gravitation (also in 1929) introduced the
group SL(2,C) into the physics of 2-component spinors (which Dirac
demonstrated are the basis of the relativistic theory of spin-1/2
particles). Weyl’s interest in group theory likely reached its
zenith in 1939, when he published The Classical Groups: Their
Invariants and Representations.
Cut to 1949. In that year, the Chinese-American physicist Chen Ning
Yang (born 1922), having recently received his PhD, took a position as
junior scientist at the Institute of Advanced Study, where Weyl had
been a senior member since his emigration to American in 1933. He
chatted occasionally with Weyl, and the two had lunch several times in
the IAS commissary, but they never discussed physics or math.
By 1954, Yang was at the Brookhaven National Laboratory, sharing an
office with the younger physicist Robert L. Mills (1927-1999), who had
not yet received his PhD. In that same year, the two published a paper
that would later represent the beginning of all modern gauge theories
for particle physics. Entitled Conservation of Isotopic Spin and
Isotopic Gauge Invariance, Yang and Mills worked out a non-Abelian
gauge theory for the group SU(2), which today is recognized as the
jumping-off point for SU(3) and quantum chromodynamics (quarks, gluons
and all that). Yang-Mills theory is beautiful, but it is
really nothing more than Weyl’s 1929 gauge idea taken one logical
step further. However, Yang-Mills languished because it initially
attempted to describe the proton and neutron as isotopic mirrors of one
another (when in fact the two particles are composite, not elementary).
Consequently, nobody really recognized the great leap the theory had
made.
Yang went on to win the 1957 Nobel Prize in Physics (with T.D. Lee) for
his work on parity violation in the weak interaction. But in 1980, he
looked back on his days with Weyl at the IAS and wondered why the two
of them had not bothered to collaborate on gauge theory:
I had met Weyl when I
went to the IAS as a young member. I saw him from time to time in the
next years, 1949-55. He was very approachable, but I do not remember
having discussed physics or mathematics with him at any time. Neither
Pauli nor Oppenheimer ever mentioned it. I suspect they also did not
tell Weyl of the 1954 paper of Mills’ and mine. Had they done
that, or had Weyl somehow come across our paper, I imagine that he
would have been pleased and excited, for we had put together two things
that were very close to his heart: gauge invariance and non-Abelian Lie
groups.
This is very strange
indeed, and a terrible loss to physics, in my opinion, because Weyl was
only to live one more year after Yang’s departure from the IAS in
1955. I would like to think that the physics community’s
recognition of the importance of Yang-Mills theory would have occurred
if Weyl had only been aware of it and championed its cause.
A sad example of a missed opportunity. Weyl suffered a heart attack and
died unexpectedly on December 8, 1955. His last spoken word was Ellen,
his wife's name.
Information -- Posted by wostraub on Monday, January 8 2007
A few nights ago the Discovery
Channel re-aired a one-hour documentary on the so-called information
paradox, which involves the question of whether or not information
(in bits or bytes or however you want to call it) can be destroyed (or
is eternal in some sense).
Until 2003, British physicist Stephen Hawking believed that information
could in fact be destroyed. Take a 1-kg stone and a 1-kg book (say,
Nabokov's Lolita) and toss each into a black hole. Hawking's
famous (if offhand sexual) remark that black holes have no hair
simply states that a black hole has only three possible attributes:
mass, angular momentum and electric charge. Thus, according to Hawking,
any kind of matter -- be it rocks or books -- simply adds to a black
hole's mass, and maybe also some angular momentum and charge, so a
black hole is an exceeding simple thing. As far as a black hole is
concerned, mass is mass, whether it's a rock or a book.
But other physicists -- notably Caltech's John Preskill -- believed
otherwise. A book contains information (at least to us humans), and it
seemed anathema that this information would be destroyed in its journey
into a black hole. Their argument went like this. Take any physical
system in a pure quantum state and drop it in a black hole. Over time,
the black hole will evaporate via Hawking radiation. Eventually (and
this may take eons), the black hole evaporates completely. Thus, the
pure quantum state is converted to a random thermal state, in violation
of quantum theory. Preskill and others believed that leaked Hawking
radiation must somehow preserve the information that's tossed into a
black hole.
In 2003, Hawking famously announced that he had been wrong all along,
though he used an argument involving parallel universes to explain why.
To date, most physicists have been dissatisfied with Hawking's
reasoning, if not his conclusion. At any rate, information seems to be
preserved.
This started me thinking about the nature of information. Does it
always exist, and we humans merely discover it? Does the sentient mind
create information? Of what use is information to the universe in the
grand scheme of things?
Claude Shannon, the noted American engineer/physicist (1916-2001)
proved that information (or knowledge) is related to probability
according to the simple (and beautiful) equation
K = -∑ p log2 p = ∑ log2 (p-p)
where K is the information (measured in bits) gained by the
observance of some event and p is the probability of the
occurrence of that event (if the event gives rise to more than one
possible observation, the probabilities have to be summed over as
indicated). Thus, the less likely some thing is, the more information
that can be gleaned from it. This (according to Imperial College's Igor
Aleksander) is the "surprise" factor: a big surprise (the
occurrence of a low probability event) conveys a lot of information.
Similarly, one of Shannon's colleagues, John Kelly, came up with the
"gambler's advantage" equation
M = eS
(see John Baez's "translation"
for Week 243), where S represents a wager's "inside
information" and M is the average expected growth of
wagered earnings. In simpler terms, the more you know, the more money
you can make. Wall Street insiders have known this for years.
Kelly's equation assumes that the inside information S is not
known by anyone else (otherwise it would not be inside information!) It
seems very suggestive to me that the applicability of this simple
equation somehow depends on the extent of the state of knowledge of one
or more people. In this sense, it is reminiscent of Schrödinger's Cat.
From these somewhat different but related points of view, information
is "good" in some fundamental sense, at least to sentient
beings. (As a Texas oilman, President Bush failed in everything he
tried, leading me to suspect he is not sentient at all, an assertion
that his presidency seems to have confirmed.)
In consideration of all this, I've led myself to the conclusion that
God is somehow the ultimate repository of all information (knowledge)
-- past, present and future -- and that the concept of what we call
"evil" is somehow related to the corruption or deliberate
obfuscation of information. I don't know if time travel to the past is
possible, but I'd like to think that all information -- whether it's
the missing 18 minutes of the Nixon tapes, the facts behind JFK's
assassination, the knowledge contained in the burned Alexandria
library, or all the stories that Neanderthals used to tell around their
campfires -- can never be truly lost to us. This seems to be confirmed
by Shannon's equation: there's no way that the information K
can be made negative. But it can be corrupted through obfuscation.
Perhaps this is why God has always expressed such an aversion to lies
and falsehoods, which tend to circumvent the truth and lead us down the
wrong paths. I just can't help but see a profound connection between
information and truth, and how it continues to elude us as a
consequence of our lying nature.