## Monday, November 17, 2008

### Lise Meitner: 130th birthday

Lise Meitner was born on November 17th, 1878, to a family of a Jewish lawyer in Vienna. She should have shared the 1944 Chemistry Nobel Prize for nuclear fission with Otto Hahn. Yes, it was the last chemistry prize that was received for nuclear physics; later, they realized that it was physics. ;-)

We will discuss both of the problems with the 1944 prize later.

According to many documents, she was born on November 7th. But the real date was probably one from the Jewish archives, November 17th. Elise Meitner had 2 older and 5 younger siblings. She has changed her name to "Lise" because Elise Meitner is not a famous name! :-)

With the money from her parents, she could attend private higher education which she completed in 1901. In 1905, she received a PhD degree from University of Vienna. Her thesis was about the thermal conductivity of non-uniform bodies. More importantly, her adviser was Ludwig Boltzmann, the "last classical physicist".

With a new PhD, she decided not to work at a gas lamp factory and went to Berlin instead. The "first quantum physicist", Max Planck, was annoyed by women in the classroom but allowed Lise to become his student. She quickly started to work with Otto Hahn, discovering new isotopes. At that time, this research was considered to be abstract - just a tool to get a Nobel prize.

In 1909, she wrote two papers on beta-radiation. In 1912, Hahn and Meitner moved to the new Emperor Wilhelm Institute (KWI) near Berlin.

Lise got an offer to work in Prague which was finally a sufficient stimulation for KWI to give her a permanent job - her first paid one, in fact. In the WW I, she served as a nurse specializing in X-ray equipment. She felt bad to return to research because so many people were suffering but she did return. She discovered the Auger effect in 1923. It's named after Pierre Auger who independently (?) re-discovered it in 1925. Since the 1930s, she and Hahn focused on trans-uranium elements. It was still considered to be abstract research, even by the citizens of Hiroshima and Nagasaki. ;-)

After 1933, she decided to ignore the Führer and hide herself in lots of work. Later, she was sorry about that decision. However, in 1938, the situation became desperate. Otto Hahn - who continued to work in Germany, collaborating with the Nazis - gave Lise a diamond ring from his mother so that she could bribe the border guards before entering Holland. She didn't need it. Otherwise, she only had 10 marks in her wallet.

She went to work to Stockholm, Sweden, showing that Manne Siegbahn who chaired the lab wasn't the "sexist discriminator" from his caricatures. She stayed in touch with Hahn who did many important experiments at that time but she couldn't publish, because of her illegal emigration. She was the first person able to use the nuclear droplet model to explain fission and argued that the electrostatic repulsion made trans-uranium elements unstable.

She was also the first person to understand that E=mc^2 explained the huge energy released in nuclear reactions. The fact that Otto Hahn got a chemistry Nobel prize wasn't just a classification idiosyncracy: Hahn actually believed that chemistry was behind the reactions. He had no explanation for his observations. Without Meitner, Hahn's work was alchemy, not serious physics.

Meitner was also the first person to say that nuclear chain reactions may lead to huge explosions. She refused to work in Los Alamos. Einstein called Meitner "our Marie Curie". After the war, Meitner participated in some blame games about Nazism and Heisenberg has heard some justified criticism from her, too. She became a Swedish citizen in 1949 but moved to England in 1960. She died in Cambridge right before her 90th birthday.

Eugene Wigner

We celebrate one more Jewish nuclear birthday today. Eugene Wigner was born 106 years ago to a middle-class Jewish family in Budapest. When he was 11, he contracted tuberculosis. At least his parents believed so. In the Austrian mountains he was getting cured and, equally importantly, began to do maths. When he was 14, a famous teacher in Budapest (László Rátz) made him really excited about mathematics.

In 1919, Bela Kun and his fu*king communist comrades established the Hungarian Soviet Republic for half a year. Wigner's family moved to Austria to escape this left-wing mess. This particular communist republic was governed by people who were both commies and Jews. Wigner's family was so upset that they converted to Lutheranism. ;-)

Since 1921, Wigner studied in Berlin where he attended talks by Planck, Laue, Heisenberg, Pauli, Einstein, and others. He befriended Leó Szilárd, worked for David Hilbert, and did other things. Since the late 1920s, Wigner was researching symmetries in quantum mechanics in which he became the world's #1 or #2. The other guy in the "Gruppenfest" was Hermann Weyl.

Wigner realized that symmetries are associated with unitary (or antiunitary) transformations - Wigner's theorem - which is why he studied them in detail.

So he's largely responsible for the 3j-symbols, 6j-symbols, Wigner-Eckart theorem, Jordan-Wigner transformation (between spin chains and fermionic creation operators) but also for the law of parity conservation. In topics that are not directly linked to symmetries, he found the semicircle distribution, the quasi-probability distribution on the phase space and its modifications (also used in the Gabor transform), the Wigner crystal, Wigner (discomposition) effect, Wigner-Seitz cell and Wigner-Seitz radius, relativistic Breit-Wigner distribution, and Wigner-d'Espagnat inequality - a normal mathematical result that was popularized in the context of Bell's inequalities etc., among other things.

Many results of Wigner's students were probably initiated in Wigner's modest mind, too. That may include Bardeen, Weisskopf, Moshinsky, Shimony, Jaynes, and Seitz - the global warming skeptic and condensed matter hero who was mentioned above and who died in 2008.

Since 1930, he worked at Princeton. In 1936, they didn't rehire him so he went to Madison where he met his first wife who died in 1937, devastating him. In 1939 and 1940, Wigner, a self-described pacifist, was important in promoting the Manhattan Project. After some annoying politically-experimental experience in the Clinton Lab in Oak Ridge, Tennessee, he returned to Princeton.

As an older guy, he focused on philosophy, including the meaning of life. In his "Wigner's friend" thought experiment - a counterpart of Schrödinger's cat - he showed that he believed that consciousness played a key role in the process of a measurement.