Eugene P. Wigner

Hungarian American physicist

• Born: November 17, 1902; Budapest, Hungary
• Died: January 1, 1995; Princeton, New Jersey

Wigner applied quantum theory to theoretical physics and focused on group theory in quantum mechanics. During World War II, he joined with other physicists in an effort to convince President Franklin D. Roosevelt of the need to develop nuclear weapons.

Also known as: Jeno Pál Wigner

Primary field: Physics

Specialty: Quantum mechanics

Early Life

Jeno Pál Wigner was born on November 17, 1902, in Budapest, Hungary, the son of Antal and Erzsebet Einhorn Wigner. His father was the director of a leather tanning factory. In 1920, Wigner graduated from the Lutheran Gymnasium (high school) in Budapest, where one of his classmates was mathematician John von Neumann, a lifelong colleague and friend. After high school, Wigner studied for a year at the Budapest Institute of Technology before transferring to Berlin’s Technische Hochschule (Technical School). He received his diploma in chemical engineering in 1924 and obtained his doctorate in engineering the next year. His doctoral dissertation, written under the direction of British Hungarian physical chemist and philosopher Michael Polanyi, discussed chemical reaction rates and the formation of molecules.

After a brief stint in his father’s factory, Wigner returned to the Technische Hochschule as a research assistant. He then spent one year at the University of Göttingen as a research assistant and lecturer in physics. Quantum mechanics was a new science, and at Göttingen Wigner became acquainted with leading figures such as Max Born, James Franck, Pascual Jordan, Walter Heitler, and Victor Weisskopf. Under their influence, he decided to reconstruct theoretical physics according to quantum theory. In 1927, his paper on group theory in quantum mechanics predated Hermann Weyl’s seminal work. Wigner also collaborated with some of his fellow theorists. He published three papers with John von Neumann on what came to be called the law of conservation of parity, which states that left and right cannot be identified in fundamental reactions. This research helped to explain what Wigner called “magic numbers.” A magic number of either protons or neutrons in a nucleus makes the nucleus unusually stable and abundant. This work would prove helpful to physicists Maria Goeppert-Mayer and J. Hans D. Jensen, who researched the underlying source of magic numbers.

Returning to the Technische Hochschule as an instructor and temporary professor, Wigner became acquainted with physicists Léo Szilárd and Edward Teller, with whom he would build lifelong associations. Around this time, Wigner researched the rates of chemical reactions and worked on the theory of metallic cohesion. He studied the structure of atoms and nuclei and the characteristics of nuclear reactions.

Life’s Work

In 1930, Wigner accepted a visiting lectureship at Princeton University. After a year, this appointment became a visiting professorship. In 1931, he published a study of group theory (a mathematical means of discussing symmetry) for physicists, Group Theory and Its Application to Quantum Mechanics of Atomic Spectra, which detailed the Wigner-Eckart theorem. This theorem was the result of the analysis of the SO(3) rotation group, and is constructed from representational theory and quantum mechanics in relation to various mathematical functions.

Wigner’s research on the neutron—the elementary particle first discovered in 1933—showed that neutrons and protons are bound together only when the binding force is very close to the particles and unaffected by the electric force that attracts the electrons to the nucleus of the atom. Throughout the 1930s, Wigner published prolifically on numerous groundbreaking topics, including the Wigner-Seitz cellular method and wave functions (1933), the Wigner-Bardeen work function (1935), and the Breit-Wigner resonance formula (1936). Wigner also developed the theory of neutron absorption, or neutron capture, wherein a target nucleus absorbs a neutron and emits a slightly different form, or isotope, of the same element.

In 1936, Wigner married fellow physicist Amelia Ziporah Frank; however, she died the following year. That year, Wigner became a US citizen and accepted an appointment as professor of physics at the University of Wisconsin. Wigner returned to Princeton University in 1938 as the Thomas D. Jones Professor of Mathematical Physics. Except for war service and some visiting appointments, he would remain at Princeton until his retirement in 1971.

Wigner’s friend and colleague von Neumann, who had come to Princeton in 1938, was the editor of the journal Annals of Mathematics. In 1939, von Neumann’s journal published Wigner’s “On Unitary Representation of the Inhomogeneous Lorentz Group.” The paper presented new ideas in both mathematics and physics, defining an elementary particle as an irreducible representation of the inhomogeneous Lorentz group.

With the beginning of World War II, several immigrant scientists—including Wigner, Léo Szilárd, Albert Einstein, and Enrico Fermi—wanted to be sure that the United States would be protected from Hitler and his totalitarian reign. In 1938, Otto Hahn and Lise Meitner of Germany had discovered nuclear fission, and, in the summer of 1939, these naturalized citizens presented their case to President Franklin D. Roosevelt, arguing that the United States needed to develop nuclear weapons. Their efforts would eventually result in the development of an atomic bomb through the Manhattan Engineering District, more commonly known as the Manhattan Project.

In 1940, Wigner produced a seminal paper dealing with the reduction of Kronecker products. The paper, which discusses the algebra of angular momentum and recoupling, includes the famous three-j symbols, now known as Clebsch-Gordan or Wigner coefficients, and the six-j symbols, now known as Racah coefficients. As the paper was privately circulated over the next decades, friends having persuaded Wigner that it was too long and difficult to understand, other researchers later rediscovered some of the same results. The paper was finally published in 1965.

When the Manhattan Project was launched in 1942, Wigner was appointed head of the theoretical section of the Metallurgical Laboratory at the University of Chicago. Applying his abilities in areas from theory to mechanical engineering, Wigner developed many of the standard techniques used in constructing reactors. After Victory in Europe Day was proclaimed in May 1945, Wigner, along with Einstein, Szilárd, and others, asked President Harry S. Truman to refrain from using the atomic bomb. But, in early August 1945, atomic bombs were dropped on Hiroshima and Nagasaki, Japan. Wigner became director of research and development at the Clinton Laboratories of Oak Ridge National Laboratory in Tennessee; between 1945 and 1947, he received thirty-seven patents on nuclear reactors. Wigner recommended the type of parallel plate reactor that was used in the Nautilus, the world’s first nuclear-powered submarine. His team also developed the isotope carbon-14.

From 1952 to 1957, and again from 1959 to 1964, Wigner was a member of the general advisory committee of the Atomic Energy Commission. He collaborated on two influential books, Nuclear Structure (1958) with Leonard Eisenbud, and The Physical Theory of Neutron Chain Reactors (1958) with Alvin M. Weinberg. In the early 1960s, Wigner also directed civil defense programs for the National Academy of Sciences and the Oak Ridge National Laboratory.

In 1963, Wigner was awarded the Nobel Prize in Physics for his systematic improvement, extension, and wide application of the methods of quantum mechanics. He shared the prize with Maria Goeppert-Mayer and J. Hans D. Jensen. The year after, Wigner published Dispersion Relations and Their Connection with Causality. In 1967, he published Symmetries and Reflections.

In 1977, Mary Annette Wheeler, Eugene Wigner’s second wife, died. In 1979, he married Eileen C. P. Hamilton. He continued to serve the government in an advisory capacity on various projects and supported President Ronald Reagan’s Strategic Defense Initiative. He also continued to write and focused on the philosophical implications and physical interpretation of quantum mechanics.

Wigner died at the age of ninety-two in Princeton, New Jersey, on January 1, 1995.

Impact

Physicist, nuclear engineer, and Nobel laureate Eugene P. Wigner is considered one of the most important figures in the history of theoretical physics. Wigner was a pioneer in the application of the principles of symmetry to predict invariances in physical processes; these symmetry principles can help predict which nuclear reactions are most likely to occur.

While mathematics had been utilized in the research and development of science, engineering, and technology, Wigner was the first to apply mathematical concepts such as group theory to quantum mechanics, the branch of physics pertaining to energy on the atomic and subatomic level.

As a member of the Manhattan Project, Wigner was responsible for applying knowledge of quantum energy toward national defense—an area to which Wigner would contribute throughout his career. In addition to his work at Princeton, Wigner served as a visiting professor at several universities in Europe. His honors include election to the National Academy of Sciences in 1945 and the vice presidency (1955) and presidency (1966) of the American Physical Society. He was presented with numerous medals and awards, including the Presidential Medal of Merit (1946).

Bibliography

Hargittai, István. The Martians of Science: Five Physicists Who Changed the Twentieth Century. New York: Oxford UP, 2006. Print. Provides biographical information on Theodore von Kármán, Léo Szilárd, Eugene P. Wigner, John von Neumann, and Edward Teller. Recounts the events of their lives and describes their important scientific discoveries.

Vogt, Erich. “Eugene Paul Wigner: A Towering Figure of Modern Physics.” Physics Today 48.12 (1995): 40–44. Print. Reviews the impact of Wigner’s research on the field of quantum mechanics. Includes photographs, a table of major milestones in Wigner’s career, and a list of references.

Weinberg, Alvin M. “Eugene Wigner, Nuclear Engineer.” Physics Today 55.10 (2002): 42–46. Print. Discusses the contributions of Wigner to nuclear engineering, including the 1936 discovery of the Breit-Wigner formula.

Wightman, Arthur S., and J. Mehra, eds. The Collected Works of Eugene Paul Wigner. New York: Springer, 2001. Print. A collection of documents on Wigner’s life and work. Compiles scientific, biographical, mathematical, and historical papers.