FBI files on Richard Feynman published

In 1955 Richard Feynman got invited to a prestigious conference in Moscow, with all the expenses payed by the Soviets.

And here we go: "The FBI found out about the proposed trip while sifting through the trash of Soviet Union Ambassador Georgi Zaroubin’s office."

In the end of the day Feynman didn't go, but the FBI surveillance continued for another few years anyway. Now we can enjoy the original documents from that time.

Take care,

Misha

Vavilov, Cherenkov, and credit for discoveries

We all know that accelerated charged particles emit light - that's how modern high-intensity light sources, synchrotrons, function. Interestingly, uniformly moving particles can emit light too.

The idea goes back to the 1904 Sommerfeld's paper, where he studied the motion of charged particles in a vacuum, and demonstrated that particles flying faster than the speed of light emit radiation even when moving uniformly [1]. Of course, the special relativity theory that appeared next year, rendered Sommerfeld's discovery just a funny mathematical result that has nothing to do with reality, since according to the special relativity no particle can move faster than light in a vacuum.

It's worth noting that the velocity restrictions imposed by the special relativity apply only to a single particle (a group velocity of a bunch of particles can be anything) moving in a vacuum (the speed of light in a medium is much smaller than in a vacuum and particles can move faster than that). However, it took more than 30 years to generalize the Sommerfeld idea to the case of charged particles propagating through a material.

Pavel Cherenkov was pursuing a PhD under Sergey Vavilov, a brother of a famous geneticist Nikolai Vavilov (who was imprisoned and eventually killed by the Soviet regime). Cherenkov was studying the luminescence of uranium salts in solutions irradiated by gamma-rays, and was quite surprised to see the "luminescence" of a pure liquid (sulfuric acid it was), with no salts added. Actually, he was convinced that his PhD work was completely ruined [2].

And it was Vavilov who suggested that this radiation was not luminescence but something completely new, and encouraged Cherenkov to continue the measurements. Indeed, very soon Igor Tamm and Ilya Frank developed a theory for the effect, showing that the radiation is emitted by electrons propagating faster than the speed of light in this particular solution. In 1958 Cherenkov, Tamm, and Frank shared a Nobel Prize for this discovery (unfortunately, without Vavilov who deceased in 1951).

Although Russians call it the "Vavilov-Cherenkov effect", it seems that the name of Vavilov is omitted in the rest of the world where people simply refer to the "Cherenkov Radiation". Why do they?

The funny thing is that immediately after the discovery Vavilov (himself) wrote a paper and submitted it to Nature, where it was rejected (!), and then to Physical Review. This paper had a single author - Cherenkov [3].

I wonder whether such an extreme academic generosity would be possible nowadays :-)

Take care,

Misha

[1] A. Sommerfeld, Göttingen Nachrichten 9, 363 (1904); 201 (1905)

[2] V. L. Ginsburg "About science and about myself" (2001)

[3] P. A. Čerenkov, Phys. Rev. 52, 378 (1937)

Getting married is dangerous

Willis Lamb (discoverer of the Lamb shift) got married three times: to Ursula Schaefer when he was 26, to Bruria Kaufman when he turned 83, and to Elsie Wattson at the age of 94. He deceased the same year, soon after his last marriage. I don't believe that's a coincidence.

Science and religion

It turns out that Georges Lemaître, who proposed the Big Bang Theory (yes, the theory itself, not the sitcom), was not only a scientist, but also a catholic priest. That's funny.

How would you know?

Here is a quote from the popular article of Nissan Zeldes "Giulio Racah and theoretical physics in Jerusalem":

"Tensor algebra is the natural mathematical tool for treating angular correlations of successive nuclear radiations, as shown first in [Racah, Rhys. Rev. 84, 910 (1951)] and independently in [Lloyd, Phys. Rev. 85, 904 (1952)]".

Well, that sounds fine. Two scientists were involved in the same kind of business and came up with similar theories about the same time - we see that everywhere in science.

The only problem is that in 1951-52 both Giulio Racah and Stuart Lloyd were working at the same place, Institute for Advanced Study in Princeton. Can one really be sure that the theories were developed independently in such a case?

When theorists are forced to do experiments

It is well known that Nobel laureate Ernest Rutherford was a brilliant but very authoritarian type of scientist. He was a head of the Cavendish lab in Cambridge and many well known scientists passed through it, such as Piotr Kapitza (Nobel Prize`78), Patrick Blackett (Nobel Prize`48), and Robert Oppenheimer (later chief of the Manhattan Project).

These three were increasingly at odds, due to their different relationships with Rutherford. While Kapitza shamelessly flattered and courted his boss, who in return gave him favours and even friendship, Blackett, who admired Rutherford's creative running of the lab, never had time for such things.

Also, Blackett was tutoring Oppenheimer by teaching him the art of experiments, for which Oppenheimer had little aptitude, and Blackett knew well about that. The tension between the two became so strong that one day Oppenheimer left on Blackett's desk an apple poisoned with chemicals from the lab (!).

Hopefully, Blacket survived, and Oppenheimer didn't lose his job only because his parents persuaded the university to put him on probation, on the understanding that he will have regular sessions with a psychiatrist.

A few months later Oppenheimer completely switched to theoretical physics.

Graham Farmelo, "The strangest man"

Not even intelligence

When famous Italian physicist Enrico Fermi was asked what characteristics Nobel prize winning physicists had in common, he said:

"I cannot think of a single one, not even intelligence."

Some photos of Albert Einstein

A famous theoretical physicist Michio Kaku posted some historical Einstein photos on his facebook page. These pictures come from Michio's private archive and are mostly not very well known.

History of science: Gulio Racah kicks ass

As many other branches of atomic, molecular, and chemical physics, the field of chemical stereodynamics emerged from nuclear physics. Basically all this business about how molecules rotate after a chemical reaction, or how to boost the reaction efficiency controlling the reagents – it was already there, in nuclear reactions and spectroscopy.

In 30's some people were involved in studying double gamma decays, when a nucleus goes from some excited state A to state B and then to the ground state C, emitting two gamma-quanta. Already in 1940 Dunworth proposed that there might be some correlations between the directions of emission of these two quanta. Here "correlations" mean that, for instance, if we detect the first gamma-ray from the upper side of the nucleus, the second one most likely will be emitted to the left, less likely to the bottom, and never to the right.

Dunworth was not able to check this experimentally, but induced Donald Hamilton to theoretically prove that there should be some correlations. A few years later Edward Brady and Martin Deutsch from MIT found an experimental evidence of gamma-gamma correlations in the decay of Co(60) and Sc(46) nuclei.

In the meantime theorists published lots of papers, step by step trying to improve approximations and thoroughly elaborate the problem. This lasted for more then a decade, from 1940 to 1951, when a brilliant article by Gulio Racah was published.

He starts it literally as: "Hey guys, last ten years I was interested in something else, but I just bumped into you and I see that you are really stuck. Well, the problem becomes very easy if you use the tensor operator algebra that I developed about a decade ago..."

And, of course, the problem turned out to be solvable in a very natural and straightforward manner. Now tensor operators is an important tool, not only in nuclear physics, but anywhere in physics in general. We all use it and like it.

Take care,

Misha


UPD: By the way, I never knew that Gulio Racah was a cousin of Ugo Fano...

Learn something every day...

The words "introvert"and "extrovert" appeared in English in 1923 upon translation of the Carl Jung's book "Psychologischen Typen" published in German two years before.

Something you should know about vodka

On the 31-st of January 1865 the author of the periodic table of elements Dmitri Mendeleev defended the doctoral dissertation "On the Combinations of Water with Alcohol":


People often say that in this piece Mendeleev proved that the solubility is the best for 40% of alcohol and 60% of water, and thereby invented vodka as we know it. Unfortunately, that's nothing but an urban legend: Russians were drinking vodka long before Mendeleev was even born.

Two quotes from Paul Dirac's letters

I certainly loose it if I don't write it up somewhere. These two quotes picked from letters to Manci Balázs, entirely describe Dirac's childhood:

i) 'I did not know of anyone who liked someone else – I thought it did not happen outside novels', 7 March 1936

ii) 'I found it to be the best policy as a child [...] to make my happiness depend only on myself and not on other people', 9 April 1935


Take care,

Misha

In fifty words or less

In his book “Indiscrete thoughts” famous Italian-born American mathematician Gian-Carlo Rota mentions that Stan Ulam was used to say “Whatever is worth saying can be stated in fifty words or less”.

Well, these days he would probably adjust it a bit:

“Whatever is worth saying can be stated in 140 symbols or less”

)

John Fenn and age discrimination

In European academia there is a mandatory retirement age: if a university professor becomes older than 65-68 years (depending on country), he cannot hold a position anymore. This was also the case in the US some 30 years ago, when the Age Discrimination in Employment Act still allowed for the mandatory dismissal of tenured workers.

A few days ago I was told a fascinating story of John Bennett Fenn. He was working at Yale for a quarter of a century, until he reached the mandatory retirement age of 70 in 1987. After a while, the law was changed to fight the age discrimination, and Fenn became officially allowed to get a job. By that time his ex-position at Yale was still vacant, and he applied for it. Believe you or not, he didn't get it.

Eventually Fenn joined Virginia Commonwealth University in 1994, where he started working on the Electrospray ionization technique, for which he shared the Nobel Prize in 2002. John Fenn was 85 by that time and he still remains the oldest Nobel Laureate in Chemistry.

Yale University claimed that Fenn was working on electrospray ionization while still holding a position there. After submitting a lawsuit against Fenn, Yale was awarded over one million dollars and partial patent rights to the technique.

The moronometer

There is a rumor that a renowned Soviet physicist Arkady Migdal thought up a device dubbed "the moronometer". That was a spool of thread placed in a breast pocket of the jacked in such a way that the thread slightly sticks out. Then Migdal was hanging around and meeting people. During such sporadic conversations a company exclaimed "Hey, you've got a thread there!", and tried to detach it, in fact unreeling the spool. Some folks kept pulling the lengthening thread for a while.

According to Migdal, the company's silliness is proportional to the resulting length of the thread.

Reference (Russian)

The Communist Thesis Competition

A PhD student of the MSU Physics Faculty, young communist V. L. Ginzburg, made a commitment to defend his thesis prior to the university's anniversary.

(source)

I don't know exactly, which anniversary is meant there: Ginzburg defended his thesis in 1940, while the MSU was founded in 1755. This might be the 185-years one.

P.S. Don't ask me what the famous theorist is doing in the lab.

Links for 01.02.09

1) A calender with naked French politicians - by Roland Hours.

2) Is massively collaborative mathematics possible? - Gowers's weblog.

3) Thousands of video lectures from the world's top scholars - a terrific project.

4) Lab-initio, a lot of funny science pictures.

5) Italian history of physics archive - some old scientific journals are accessible after free registration.

6) Leningrad Siege: Now and then, from English Russia - shows how Saint Petersbourg waw looking during WWII.

Old books with Google

I never mentioned that apart from partial preview, Google books offers some full-text books to read and download. For, instance, here are books in math, which are out of copyright and can be read for free. Of course, most of them are old, and even ancient as, for instance, "Arithmetical Tables Fitted to the Capacity of Such as are Unskilled in the Art of Numbers" by Henry Walrond, published in 1663. The book describes how to work with numbers, add and subtract them. 

What is interesting for me is the old English, this book is written in. Previously I thought that it will be extremely hard for me to read such old printings. But, surprisingly enough, there is no big difference with the modern language. There are some funny words there, for instance "shew" and "your self", instead of "show" and "yourself".

I wonder why Google finds many more copyright-free books in mathematics, than in physics or in chemistry...

The Monte-Carlo method

I was actually not aware of the fact that the Monte-Carlo method of integration was proposed by Stan Ulam working on Manhattan project at Los Alamos. I also like his aphorism, which I came across of here:

"My late friend Stan Ulam used to remark that his life was sharply divided into two halves. In the first half, he was always the youngest person in the group; in the second half, he was always the oldest. There was no transitional period."

Secret History of Quantum Physics

An interesting post by Chad Orzel, about the great discoveries made during vacations:

"Erwin Schrödinger famously discovered the equation that bears his name while on a skiing holiday in 1925. He was accompanied on this vacation by one of his many girlfriends, but which of them went on the fateful trip has been lost to history-- Schrödinger kept exceedingly detailed diaries, but the volume covering the relevant period has been lost."

I'm eager to know, who was his girlfriend...