Historical Quantum Smackdown Explained

This was delayed a day by yesterday's ranting, but I wanted to explain the significance of the people in Monday's lesser-known quantum mechanic smackdown. I'm happy to see that, as of this morning, three candidates have rallied past the "unique flower" option.

In reverse order of popularity:

Hendrik Kramers was a Dutch physicist who spent a long time working as a student and assistant to Bohr, and thus was involved in a lot of the early attempts to make a working quantum theory. He's best known for work in condensed matter physics, and for being the "K" in the WKB approximation.

Arnold Sommerfeld was another physicist who did a great deal of work with the early quantum models, trying to extend Bohr's original model of hydrogen. He also contributed significantly to early solid state physics, and has a few equations named after him. His greatest contribution was probably in the area of education, though, as he was the Ph.D. advisor to an impressive list of people.

Paul Ehrenfest was an Austrian physicist who is best known for Ehrenfest's theorem, which shows that while quantum particles may individually do weird things, the average of a property over a large number of quantum measurements (the "expectation value") will obey classical rules. That is, if you subject a bunch of electrons to a known force, and measure their position, some of them will be well ahead of or well behind the place you would predict using classical rules. The average position of all the electrons together, though, will be consistent with what you would get using Newtonian physics.

Ehrenfest is a sort of tragic figure, who made valuable contributions to quantum theory, and was close friends with many of the great physicists of the day. He struggled with depression for many years, and eventually killed himself and his youngest son.

I'm a little surprised to see George Gamow tied for second, as he was a late addition to the list. Gamow's main contribution to quantum physics was the idea of nuclear decay as a tunneling process, though he's better known for the α-β-γ paper on nucleosynthesis (which was work done by his student, Ralph Alpher, with Hans Bethe added as a joke without the knowledge of Alpher or Bethe).

Gamow probably rates as highly as he does because of his work as a popularizer of science, through the whimsical Mr. Tompkins stories about a bank clerk who daydreams about relativity and quantum mechanics, and 1, 2, 3... Infinity. He also has one of the best personal stories of any physicist, as his Wikipedia entry includes:

Gamow then worked at a number of Soviet establishments before deciding to flee Russia because of increased oppression. His first two attempts to defect with his wife, Lyubov Vokhminzeva, were in 1932 and involved attempting to kayak: first a 250 kilometer paddle over the Black Sea to Turkey and then from Murmansk to Norway. Poor weather foiled both attempts. In 1933, the two tried a less dramatic approach--Gamow managed to obtain permission for himself and his wife (who was also a physicist) to attend the Solvay Conference for physicists in Brussels. The two attended and promptly defected.

That's right, his first plan involved kayaking 150 miles over the Black Sea. This was not your typical physics nerd.

Tied with Gamow in the #2 spot is Eugene Wigner, a Hungarian physicist who did a lot of work establishing the role of symmetry in quantum mechanics. There are a whole host of equations and theorems bearing his name, the most important of which, for me, is the Wigner-Eckart theorem. It's important because it comes up frequently in atomic physics, and I can never remember what the hell it says, despite having been asked about it about a thousand times while preparing for my thesis defense.

He's also famous for thinking deep thoughts about the nature of reality, as exemplified by the famous essay The Unreasonable Effectiveness of Mathematics in the Natural Sciences. He also extended the Schrödinger cat thought experiment, adding what's known as "Wigner's friend:" you imagine that the usual cat experiment was performed by somebody else, who then reports the result to you. The question is, at what point is the cat's fate determined: when the box was opened, or when you were told about the result? Try that one on your local stoners...

The overall winner of the poll was Max Born, another German physicist who is famous for figuring out the connection between wavefunctions and probability. The relation used to calculate probablilities from wavefunctions is properly known as the "Born rule," but the name is frequently left out. Born thus also serves as an example of the way that a problem in physics can shift overnight from "impossible" to "trivial."

Born arguably should have shared the 1932 Nobel Prize with Heisenberg, because he was instrumental in helping Heisenberg develop the matrix formulation of quantum mechanics (with Pascual Jordan), but he didn't get his Nobel until 1954. He was reportedly a little bitter about this for those twenty years.

Born is also well known to molecular physicists and chemists, for the Born-Oppenheimer approximation, one of the most important tricks for making molecular physics tractable. Any time you see a professor drawing an interaction potential for atoms in a molecule, they're probably implicitly using the Born-Oppenheimer approximation.

So those are the most important lesser-known quantum pioneers, or at least the ones I could think of Monday morning when I wrote that poll...

More like this

what happened to Hermann Weyl ?

what happened to Hermann Weyl ?

He died in Zurich in 1955. Why do you ask?

(I didn't think of Weyl when I was hastily putting that poll together.)

On the subject of the 1932 Nobel Prize for physics, they were evidently quite careful how they awarded it. The prize was not awarded in 1932 but held until 1933, when it was given simultaneously with the 1933 prize, which went to Schroedinger and Dirac. Thus, the two creators of quantum mechanics received their prizes simultaneously, but Heisenberg (having developed his version of the theory first) received a solo prize, while Schroedinger had to share.

I was going to say "What happened to Olivia Newton John", but instead I'll make the following observation:

The Wigner-Eckart theorem tells you that any physical calculation can be split into two parts: one contains the boring and semi-uninteresting angular dependence that is there simply because of the geometry of nature, and the other (the "reduced" matrix element) contains all of the physics of the problem in question.

A weak analogy might be to the decision to use Cartesian coordinates for projectile motion on the earth but polar coordinates for simple circular motion of a mass on a string -- matching the mathematical representation to the geometrical symmetry of the physics within the problem.

I think when you mention Pascual Jordan you might consider qualifying his contributions by noting his enthusiastic membership in the Nazi party. The Nobel committee may have avoided awarding a shared prize in 1932 to Born and Heisenberg as they would then have been obligated to also honor PJ.

I think when you mention Pascual Jordan you might consider qualifying his contributions by noting his enthusiastic membership in the Nazi party. The Nobel committee may have avoided awarding a shared prize in 1932 to Born and Heisenberg as they would then have been obligated to also honor PJ.

The Nazi thing is alleged to be the reason for Heisenberg getting a solo prize. And Born's 1954 prize was for a slightly different subject, so it could rightly be given to him alone, without recognizing Jordan, who was still alive at the time.

I left it out because it's a bit of a thorny subject, and not all that relevant to the topic at hand.

Certainly the Nobel Prize politics is not all that relevant. But I believe Jordan's Nazi affiliation should be mentioned whenever his name is brought up, lest people walk away with a favorable impression of him.

First, certainly pleased that Born won the poll. Second, don't want to make a big deal but feel it necessary to respond to the Jordan comment. Jordan became a member of the Nazi party in the last week of April 1933. The Swedish physicist Carl Oseen,chair of the Nobel Academy's committee on physics, determined the winners in the fall of 1933. It is highly unlikely that he knew of Jordan's affiliation at that time. Given Oseen's negative opinions about the QT matrix formulation expressed in his committee reports, it is much more likely that Oseen was the reason Born did not receive a prize that year. In fact, Born did not receive his prize until Oseen retired. Jordan deserves blame but not for Born's missing the 1932 prize.

By Nancy Greenspan (not verified) on 03 Sep 2009 #permalink

Einstein was right about the shortcomings of Quantum Mechanics and so therefore String Theory is also the incorrect approach.
As an alternative to Quantum Theory there is a new theory that describes and explains the mysteries of physical reality. While not disrespecting the value of Quantum Mechanics as a tool to explain the role of quanta in our universe. This theory states that there is also a classical explanation for the paradoxes such as EPR and the Wave-Particle Duality. The Theory is called the Theory of Super Relativity and is located at: http://www.superrelativity.org
This theory is a philosophical attempt to reconnect the physical universe to realism and deterministic concepts. It explains the mysterious.