Eugene Paul Wigner (born 17.09.1902) is an American theoretical physicist and a member of the National Academy of Sciences (1945). He was born in Budapest. He graduated from the Higher Technical School in Berlin (1925). In 1930-71 he worked at Princeton University (professor from 1938), and in 1942-45 at the Metallurgical Laboratory of the University of Chicago.
His work concerned quantum mechanics and electrodynamics, nuclear physics, the theory of nuclear reactors and elementary-particle physics. He was one of the first to show how effective the apparatus of group theory is when applied to quantum mechanics, and he did much to establish the ideas of symmetry and group theory in modern theoretical physics; he laid the foundations of the theory of symmetry in quantum mechanics and introduced ideas and methods, applying them to fundamental problems.
In 1927, together with P. Jordan, he constructed a formalism equivalent to wave mechanics in configuration space with antisymmetric wave functions, developed the method of second quantisation, and in 1928 carried out the quantisation of the electron field. In 1927 he introduced the idea of the parity of the wave function, and in the same year discovered mirror symmetry (the conservation of spatial parity) and formulated the law of conservation of parity, and in 1932 symmetry with respect to time reversal. In 1933 he showed that nuclear forces have a small range of action (are short-range). In 1937, independently of others, he introduced the concept of isotopic spin and was the first to formulate clearly the law of conservation of isotopic spin in nucleon-nucleon interactions. In 1937 he pointed out the connection between isospin and the charge independence of nuclear forces.
Together with G. Breit he proposed in 1936 a dispersion formula for the cross-section for the capture and scattering of neutrons (the Breit — Wigner formula). In 1937 he proposed a uniform model of the nucleus (the Wigner model) and applied it to the study of nuclei heavier than oxygen. He showed (1939) that a chain nuclear fission reaction can proceed in uranium. As a member of E. Fermi's group he took part in the construction of the first American atomic reactor, and he led the work in the United States on the theory of nuclear reactors.
In 1949 he formulated the law of conservation of baryon charge, and in 1952 he examined the consequences that follow from the laws of conservation of electric and baryon charge. For his contribution to the theory of the atomic nucleus and of elementary particles, and especially for the application of fundamental principles of symmetry, he was awarded the Nobel Prize in 1963. In 1935 he carried out the first calculation and estimated the pressure of the transition of molecular hydrogen into the metallic state.
He is an honorary member of many academies of sciences and scientific societies. In 1956 he was president of the American Physical Society. The B. Franklin (1950), E. Fermi (1958) and M. Planck (1961) Medals, the Atoms for Peace Award (1960) and others.