Akademik

Born the son of a businessman in Budapest, Hungary, Wigner was educated at the Berlin Institute of Technology, where he obtained a doctorate in engineering in 1925. After a period at Göttingen he moved to America in 1930 and took a part-time post at Princeton. He became a naturalized American citizen in 1937 and in 1938 was appointed to the chair of theoretical physics. Wigner remained at Princeton until his retirement in 1971 apart from leave of absence when he served at the Metallurgical Laboratory, Chicago (1942–45), and at Oak Ridge as director of the Clinton Laboratories (1946–47).

Wigner made many fundamental contributions to quantum and nuclear physics. He did some early work on chemical reactions and on the spectra of compounds. In 1927 he introduced the idea of parity as a conserved property of nuclear reactions. The basic insight was mathematical and arose from certain formal features Wigner had identified in transformations of the wave function of Erwin Schrödinger. The function Ψ (x,y,z) describes particles in space, and parity refers to the effect of changes in the sign of the variables on the function: if it remains unchanged the function has even parity while if its sign changes it has odd parity. It was proposed by Wigner that a reaction in which parity is not conserved is forbidden.

In physical terms this meant that a nuclear process should be indistinguishable from its mirror image; for example, an electron emitted by a nucleus should be indifferent as to whether it is ejected to the left or the right. Such a consequence seemed natural and remained unquestioned until 1956 when Tsung Dao Lee and Chen Ning Yang shocked the world of physics by showing that parity was not conserved in the weak interaction.

In the 1930s Wigner made major contributions to nuclear physics. Working particularly on neutrons he established early on that the nuclear force binding the neutrons and protons together must be short-range and independent of any electric charge. He also with Gregory Breit in 1936 worked out the Breit–Wigner formula, which did much to explain neutron absorption by a compound nucleus. Wigner was involved in much of the early work on nuclear reactors leading to the first controlled nuclear chain reaction.

Wigner shared the 1963 Nobel Prize for physics with Maria Goeppert Mayer and J.Hans Jensen for “systematically improving and extending the methods of quantum mechanics and applying them widely.”