Wigner, Eugene Paul

(b. 17 November 1902 in Budapest, Hungary, d. 1 January 1995 in Princeton, New Jersey), mathematical physicist who made numerous pioneering contributions to quantum mechanics and fundamental nuclear theory, for which he received the Nobel Prize in physics in 1963.

Eugene Paul (Jenó Pál in the Hungarian) Wigner was born in Budapest, the second of three children, to Anthony Wigner and Elizabeth Einhorn. His father ran a leather-making factory and both parents put a strong emphasis on education for their children. While attending Budapest Lutheran High School, Wigner was especially interested in physics and mathematics; however, after his high school graduation in 1920, practical concerns led him to enroll as a chemical engineering student at the Berlin Technische Hochschule (Institute of Technology) in Germany. He received an undergraduate degree in 1924 and a Ph.D. in chemical engineering in 1925 under the direction of another Hungarian scientist, Michael Polányi.

He returned to Budapest for one year to work in a leather-tanning factory but returned to Berlin in 1926 to take a post as a research assistant at the Technische Hochschule. This association began his first important exposure to the new field of quantum physics. Employing his exceptional mathematical aptitude he began exploring how group theory, a classical study first developed in the nineteenth century by the Norwegian mathematician Sophus Lie, might be applied to quantum mechanics. As the result of this work, Wigner was invited by the great German mathematician David Hilbert to join him at the University of Göttingen. At Göttingen, Wigner conducted his early investigations into the significant connection between rules of mathematical symmetry and corresponding conservation laws of physics—a connection that decisively influenced quantum mechanics and the growing understanding of nuclear structure.

In 1928 Wigner returned to the Technische Hochschule as a lecturer, staying until 1930, when he emigrated to the United States to accept a position as an instructor in physics at Princeton University in New Jersey. Most of Wigner’s career was spent in Princeton. During the period 1936–1938 he joined the University of Wisconsin as professor of physics. He returned to Princeton in 1938 and was named the Thomas D. Jones Professor of Mathematical Physics at the Palmer Physical Laboratories. Along with many other scientists during World War II, Wigner departed from his academic activities to apply himself to military research. Wigner was among the chief theoreticians under the leadership of Enrico Fermi in achieving the first nuclear chain reaction. Fermi, an Italian physicist with an extraordinary combination of abilities in both theoretical and experimental physics, had left his native country in 1938 because of the jeopardy he felt his Jewish wife could encounter under Benito Mussolini’s fascist dictatorship.

The chain reaction was accomplished with a natural uranium-fueled, graphite-moderated assembly (an “atomic pile”) in a squash court under the west stands of Stagg football field at the University of Chicago on 2 December 1942. The scientific team then sent a coded telephone message to the administration in Washington, D.C.: “the Italian navigator has just landed in the new world.” Wigner toasted Fermi with a celebratory bottle of Chianti wine but later recalled in a more serious vein: “For some time we had known that we were about to unlock a giant. Still we could not escape an eerie feeling when we knew we had actually done it. We felt as I presume everyone feels who has done something that he knows will have far-reaching consequences which he cannot foresee.”

This milestone in nuclear science—indeed in the history of mankind—had its origin in an earlier event in which Wigner had played a pivotal role. While in Berlin in the 1920s, Wigner had become friends with fellow scientists from Hungary, Leo Szilard and Edward Teller. At different times they each emigrated along with many other scientists from a Europe that was becoming dominated by Hitler, threatening the livelihood, freedom, and lives of Jews, intellectuals, and political adversaries. Szilard was the first to recognize the potentially serious problem created by the discovery of neutron-induced fission in the element uranium by the German chemists Otto Hahn, Fritz Strassman, and the Austrian-Jewish physicist Lise Meitner.

In 1939 Szilard enlisted Wigner and Teller to discuss the threat of an atomic bomb with Albert Einstein. They felt that only Einstein had sufficient prestige and influence to convey the urgency of the serious problem to President Franklin Delano Roosevelt. Einstein understood the problem at once and immediately signed the letter prepared by the Hungarian immigrants. Though Einstein played no subsequent role in atomic bomb development, his message to Roosevelt is regarded as the catalyst that led to the massive Manhattan Project, which resulted in the successful development of the uranium bomb that devastated Hiroshima on 6 August 1945 and the plutonium weapon that struck Nagasaki three days later, ending World War II.

Although Wigner, Szilard, and Teller had started the program and contributed importantly to technical phases of building the nuclear weapons subsequently used against Japan, they ultimately urged that the bomb not be used. They expressed their objections to the Hiroshima bombing in the form of a petition (written by Szilard) that received the signatures of sixty-seven other Manhattan Project scientists. The administration of Harry S. Truman nonetheless decided to drop the bomb.

From 1946 to 1948, before returning to Princeton, Wigner was director of research and development at the Clinton Laboratories in Oak Ridge, Tennessee (later to become Oak Ridge National Laboratory), a group of four hundred scientists and technical staff engaged in research and development under government contract. At the time, the reactors at the site were the principal source of radioactive isotopes for use in fundamental atomic research and for human applications in medical diagnosis using tracers and therapy in the treatment of cancer.

On 13 December 1963 Wigner shared the Nobel Prize in physics with Maria Goeppert Mayer and J. Hans D. Jensen for their separate discoveries in the theory of the nucleus and fundamental atomic particles. Unlike most Nobel scientific awards, which are generally given for unique single discoveries or inventions, the award to Wigner recognized his contributions to many different areas of nuclear physics over a period beginning in the late 1920s and extending for more than three decades.

Among Wigner’s accomplishments was the recognition that symmetry principles explained patterns found in atomic and molecular spectra. Wigner’s analysis of the application of mathematical group theory enabled physicists to understand relative stability or instability of nuclear isotopes having the same number of protons in the nucleus but different neutron numbers. Nearly a decade after he was awarded the Nobel Prize, Wigner’s early group theory research was described as so farsighted that it was not immediately recognized for its importance as a pioneering advance in mathematical physics.

Interestingly referenced in the Nobel Prize presentation to Wigner was his law of the conservation of parity developed at Göttingen in 1928. The parity law states that particles emitted during a physical process should emanate from the left and right in equal numbers or equivalently that a nuclear process should be indistinguishable from its mirror image. The parity concept was not challenged until 1956 when it was disproved in certain so-called “weak decay” interactions in experiments by Tsung-Dao Lee of Columbia and Chen Ning Yang of Princeton. Lee and Yang were awarded the Nobel Prize in 1957 for their empirical refutation of Wigner’s parity theory in this special case. The theory however remained substantially intact and along with other of Wigner’s discoveries useful as a further guide in nuclear research.

Several aspects of Wigner’s career outside of pure physics caused significant controversy. In the 1960s he pursued methods of protection against nuclear weapons effects which presumed that nuclear war might be survivable if suitable civil defense measures were taken. The advent of hydrogen bombs a thousand times more powerful than the atomic weapons employed against Japan made the defense measures advocated by Wigner questionable. Wigner also found himself among the minority of scientists who defended Edward Teller’s critical testimony in a loyalty hearing that was influential in leading to J. Robert Oppenheimer, the scientific head of the Manhattan Project, losing his government secret security clearance in 1954. Wigner’s public defense of Teller was more a case of personal confidence and trust in his long-time friend, rather than Wigner’s own doubts about Oppenheimer’s loyalty.

In 1936 Wigner married Amelia Z. Frank, who died in 1937. That year Wigner became a naturalized citizen of the United States. In 1941 he married Mary Annette Wheeler, a professor of physics at Vassar College in Poughkeepsie, New York. They had two children. After his second wife’s death in 1977, he married Eileen Hamilton in 1979, and they had a daughter. Wigner retired as professor emeritus from Princeton in 1971. He died of pneumonia at the age of ninety-two at the Medical Center in Princeton.

Along with the Nobel Prize, he was the recipient of honorary doctorate degrees from Princeton and twenty-six other colleges and universities in the United States, Europe, and Israel. In 1958 he received the U.S. Atomic Energy Commission Enrico Fermi Award and in 1972 the Albert Einstein Award. In 1990 he became the first recipient of the American Nuclear Society Award designated thereafter the Eugene P. Wigner Award. That same year, after the fall of the communist government in his native Hungary, he received the Order of the Banner of the Republic with Rubies, followed in 1994 by Hungary’s highest honor, the Order of Merit “as an acknowledgment of his scientific career and of his outstanding achievements in the enrichment of universal human values.” In his 1960 paper “The Unreasonable Effectiveness of Mathematics in the Natural Sciences,” Wigner explained the importance of mathematics:

The miracle of the appropriateness of the language of mathematics for the formulation of the laws of physics is a wonderful gift which we neither understand nor deserve. We should be grateful for it and hope that it will remain valid in future research and that it will extend, for better or for worse, to our pleasure even though perhaps also to our bafflement, to wide branches of learning.

The Eugene Paul Wigner Papers are held at Princeton University’s library. His writings are being compiled in the eight-volume Collected Works of Eugene Paul Wigner (1993), edited by Arthur Wightman. See The Recollections of Eugene P. Wigner as Told to Andrew Szanton (1992) for Wigner’s look back at his life and work. Wigner’s sister Margit was married to the eminent English theoretician Paul Dirac, and in Reminiscences About a Great Physicist: Paul Adrien Maurice Dirac (1987), edited by Wigner together with Behram N. Kursunoglu, the point of view of one great scientist for another reveals much about the character of each of them. Richard P. Hewlett and Oscar E. Anderson, Jr., The New World: A History of the United States Atomic Energy Commission, vol. 1, 1939–1946, and vol. 2, 1947–1952 (1962), is a journalistic account that gives prominent reference to Wigner’s contributions to nuclear weapons and, later, reactor development. Also see G. Emch, “The Philosophy of Eugene P. Wigner,” in Classical and Quantum Systems (1993). Tributes to Wigner in the months after his death appeared in Current Science 69 (1995): 375-385 and Physics Today 48, no. 12 (1995): 40-44. John Gibbon, Q Is for Quantum: An Encyclopedia of Particle Physics (1998), is a useful source for terminology and expositions of concepts in Wigner’s research as well as brief biographical information. An obituary is in the New York Times (4 Jan. 1995).

Leonard R. Solon