The Hungarian-born American physicist Eugene Paul Wigner (1902-1995) formulated symmetry principles and, together with group theory, applied them in atomic, nuclear, and elementary particle physics.

On November 17, 1902, Eugene P. Wigner was born in Budapest, the son of Anthony Wigner, a leather manufacturer, and Elisabeth Einhorn Wigner. In 1920 he entered the Technical Institute in Budapest, where, at his father's urging, he concentrated on chemical engineering although his principal interest lay in mathematics. A year later he transferred to the Technische Hochschule in Berlin, still majoring in engineering. However, before long he was a regular visitor at the physics colloquia attended by some of the chief leaders in physics in Germany at that time, including Albert Einstein, Walther Nernst, and Max Planck.

Wigner's doctoral thesis was on the formation and disintegration of molecules. After a year and a half of work as leather chemist, Wigner eagerly accepted the offer of an assistant professorship at the Technische Hochschule in Berlin, where, in the late 1920s and early 1930s, his attention turned toward the exploration of symmetry principles in atomic physics. Related to this was Wigner's recognition that group theory, a branch of mathematics inaugurated almost 100 years earlier, could be used to great advantage in accounting for the quantum mechanical interpretation of atomic spectra. His book on this topic, Gruppentheorie and ihre Anwendung auf die Quantenmechanik der Atomspektren (1931; trans. in 1959 as Group Theory), is a classic in the field.

Wigner's stay in Berlin ended in 1933 when the Nazis came to power. His first post in the United States was at Princeton University, the second at the University of Wisconsin (1937-1938). In 1938 he returned to Princeton as Thomas D. Jones professor of mathematical physics. During the 1930s Wigner followed with keen interest research on neutron capture, and he was one of the first to realize its awesome and immediate potentialities.

In 1936 Wigner married Amelia Z. Frank. She died the following year. In 1941 he married Mary Annette Wheeler, and they had two children, David and Martha. After her death Wigner married Eileen Hamilton and had another daughter, Erika.

Among his early efforts to alert the government of the United States was his visit, in the summer of 1939 with Leo Szilard, to Albert Einstein on Long Island. What happened made history. At Wigner's and Szilard's pleading, Einstein consented to address a letter to President Roosevelt about the urgency of producing atomic weapons. In the actual production of the first atomic bomb, Wigner's role was crucial.

Wigner not only took a most active part in achieving the first controlled nuclear reaction in Chicago in December 1942, but it became his task to design the first large-scale nuclear reactor. His secret report of January 9, 1943, outlined the details of the huge reactor, a million times more powerful than the first, to be built near the banks of the Columbia River. The gigantic measure of problems to be solved can be gauged from the fact that Wigner's design called for 200 tons of uranium and 1,200 tons of graphite. He also successfully argued that the cooling should be done by water running throughout the whole graphite structure in pipes whose central part contained the uranium. It is safe to assume that Wigner's feat saved about a year in the production of the bomb and also in the duration of the war. After the war he remained a leader in the investigation of the very essence of reactor theory, the neutron chain reaction, as evidenced by his authoritative work written jointly with A.M. Weinberg, The Physical Theory of Neutron Chain Reactors (1958).

In the 1950s but especially in the 1960s, Wigner's attention increasingly turned to some fundamental questions of physical science and to their major philosophical implications. His articles "Invariance in Physical Theory" (1949), "Conservation Laws in Classical and Quantum Physics" (1954), "The Problem of Measurement" (1963), and "Symmetry and Conservation Laws" (1964) have already proved their lasting value. As to the philosophical ramifications of physics, the same holds for his papers "The Limits of Science" (1950), "The Unreasonable Effectiveness of Mathematics in Natural Sciences" (1960), "Two Kinds of Reality" (1964), and "The Probability of the Existence of a Self-reproducing Unit" (1961).

Wigner's main scientific distinctions are the Nobel Prize in physics for 1963 and the Max Planck Medal of the German Physical Society (1962). His adopted country gave him the Medal for Merit, the Enrico Fermi Prize, the Atoms for Peace Award, and the Albert Einstein Award. In 1990 Wigner received the Order of the Banner of the Republic of Hungary with Rubies from his newly democratized birthplace, Hungary. In 1994, he was presented with Hungary's highest recognition, the Order of Merit.

Most significantly, in 1963, is Wigner's award of the Nobel physics prize for "systematically improving and extending the methods of quantum mechanics and applying them widely." Specifically, he was commended for his contribution to the theory of atomic nuclei elementary particles, especially for his discovery and application of fundamental principles of symmetry. This marked an unusual departure for the Nobel Committee, which normally awards the prize for a single discovery or invention.

Wigner, who retired from Princeton in 1971, was also active on behalf of other scientists. He was one of thirty-three Nobel Prize winners who sent a telegram to President Podgorny of the former Soviet Union asking that Andrei Saktlarov be permitted to receive the Nobel Peace Prize in Stockholm.

His dedication to the defense of America's freedom, and of freedom everywhere, constitutes indeed a major aspect of his life and activities. It was the same unconditional appreciation of freedom, whether threatened by dictatorship from the right or the left, that determined Wigner's position amidst the debates on nuclear armament and civil defense. His philosophy is best evidenced by his insistence on the crucial importance of the role of nonscientists in the modern scientific world: "The struggle for men's minds continues and it is quite possible that the conflict between democracy and dictatorships will be won not by armies, not even by scientists, but by philosophers, psychologists, and missionaries who articulate and communicate our ideals."

Wigner died from pneumonia at the age of 92 on Sunday, January 1, 1995.

Further Reading

• Wigner's Symmetries and Reflections: Scientific Essays (1967) contains a selection of his less technical papers on a wide range of subjects. There is no comprehensive account of Wigner's life and work. A profile of him appears in Robert H. Phelps, Men in the News--1958: Personality Sketches from the New York Times (1959). The history of modern physics, of which he was a part, is entertainingly given in George Gamow, Biography of Physics (1961). The extensive use of group theory in physics is fully discussed in Morton Hamermesh, Group Theory and Its Application to Physical Problems (1962).