Gregory Breit
Gregory Breit
Russian–American physicist (1899–1981)
Although born in Nicholaev, Russia, Breit moved to America in 1915 and became a naturalized citizen in 1918. He studied at Johns Hopkins University, gaining his PhD in 1921. From 1921 until 1924 he worked successively at the universities of Leiden, Harvard, and Minnesota, before joining the Carnegie Institution, Washington (1924–29).
At Carnegie, Breit worked in the department of terrestrial magnetism as a mathematical physicist, and it was there that he conducted, with Merle A. Tuve, some of the earliest experiments to measure the height and density of the ionosphere. Their technique was to transmit short bursts of radio waves and analyze the reflected waves received. Their work is now seen as a significant step in the historical development of radar.
Besides his pioneering studies of the ionosphere, Breit also worked on quantum theory, nuclear physics, and quantum electrodynamics. In particular, he and Eugene Wigner were able to show that the experimental observations of the interactions of neutrons and protons indicated that the particles differed only in their charge and other electrical properties, and not in their nuclear forces. The Breit–Wigner formula is a formula for the energy dependence of the absorption cross-section of a compound nucleus in a nuclear reaction.
Between 1929 and 1973 Breit held professorial posts at the universities of New York, Wisconsin, and Yale, and the State University of New York, Buffalo.
Gregory Breit
Gregory Breit (Russian: Григорий Альфредович Брейт-Шнайдер; July 14, 1899, Mykolaiv – September 11, 1981, Salem, Oregon) was an American physicist and professor at universities in New York, Wisconsin, Yale, and Buffalo. In 1921, he was Paul Ehrenfest's assistant in Leiden.
In 1925, while at the Carnegie Institution of Washington, Breit joined with Merle Tuve in using a pulsed radio transmitter to determine the height of the ionosphere, a technique important later in radar development.[1]
Together with Eugene Wigner, Breit gave a description of particle resonant states with the relativistic Breit–Wigner distribution in 1929, and with Edward Condon, he first described proton-proton dispersion. He is also credited with deriving the Breit equation[2]
In April 1940, he proposed to the National Research Council that American scientists observe a policy of self-censorship due to the possibility of their work being used for military purposes by enemy powers in World War II.[3]
During the early stages of the war, Breit was chosen by Arthur Compton to supervise the early design of the first atomic bomb during an early phase in what would later become the Manhattan Project. Breit resigned his position in 1942, feeling that the work was going too slowly and that there had been security breaches on the project; his job went to Robert Oppenheimer, who was later appointed to scientific director of the entire project.
Breit was Associate Editor of the Physical Review four times (1927-1929, 1939-1941, 1954-1956, and 1961-1963).
He was awarded the Franklin Medal in 1964. In 1967, he was awarded the National Medal of Science.[4]
References
- ^ Breit, G., and M. A. Tuve; "A Test of the Existence of the Conducting Layer," Phys. Rev, vol. 28, p. 554, 1926
- ^ Bethe, A., and E. E. Selpeter; Quantum Mechanics of One- and Two-Electron Atoms, Plantum Press, 1977, p. 181
- ^ Weart, Spencer R.; "Scientists with a Secret," Physics Today, vol. 29, 1974, pp. 23-30
- ^ National Science Foundation - The President's National Medal of Science
External links
- Annotated Bibliography for Gregory Breit from the Alsos Digital Library for Nuclear Issues
- Biographical Memoirs of Gregory Breit by McAllister Hull
- National Academy of Sciences Biographical Memoir
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