This entry contributed by Leonardo Motta

Italian-American physicist who was born in Rome on September 29, 1901. In 1918, he was awarded a fellowship at the Normale Superiore de Pisa, where he received his physics doctorate in 1922 under Professor Puccianti. Soon afterwards, he was awarded a scholarship from the Italian government to study some months in Göttingen with Max Born. He then moved to Leyden with a Rockefeller Fellowship in 1924, and in the same year returned to Italy to occupy the chair of lecturer in physics at the University of Florence.

In 1926, Fermi discovered the statistical laws, now called Fermi-Dirac statistics, that govern the particles subject to the Pauli exclusion principle. Such particles are called fermions in Fermi's honor. In the following year, Fermi was appointed professor of theoretical physics at the University of Rome, a post that he retained until 1938 when, immediately after receiving the Nobel Prize in physics for his studies on the artificial radioactivity produced by neutrons and for nuclear reactions of slow neutrons, escaped to United States to avoid Mussolini's fascism (and persecution of his wife, who was Jewish).

During the early years of his career in Rome, Fermi studied problems in electrodynamics and performed theoretical investigations on various spectroscopic phenomena. However, Fermi's most important work began when he directed his attention from the outer electrons to the atomic nucleus itself. In 1934, he evolved the beta decay theory, coalescing previous work on radiation theory with Pauli's idea of the neutrino. Following the discovery by Marie Curie and Frédéric Joliot-Curie of artificial radioactivity (1934), he demonstrated that nuclear transformation occurs in almost every element subjected to neutron bombardment. This work resulted in the discovery of slow neutrons that same year, subsequently leading to the discovery of nuclear fission and the production of elements lying beyond the known portion of the periodic table (i.e., the transuranium elements).

Upon arriving in the United States, Fermi was appointed professor of physics at Columbia University, in New York. Following the discovery of fission by Hahn and Strassman early in 1939, he immediately saw the possibility of the emission of secondary neutrons and of a chain reaction. He proceeded to work with tremendous enthusiasm, and directed a classic series of experiments which ultimately led to the construction of an atomic pile which produced the first controlled nuclear chain reaction. This took place in Chicago on December 2, 1942 in a volleyball field situated beneath the University of Chicago's sports stadium.

Fermi subsequently played an important part in solving the problems connected with the development of the first atomic bomb, and was one of the leaders of the team of physicists on the Manhattan Project for the development of the atomic bomb. Fermi became a American citizen in 1944 and, at the end of the war in 1946, accepted a professorship at the Institute of Nuclear Studies at the University of Chicago, a position he held until his death. While at Chicago, Fermi founded a group for high-energy physics research, including the pion-nucleon interaction. Fermi died in Chicago on November 29, 1954.

Curie (Marie), Hahn, Joliot-Curie (Frederic), Strassman