Julian Schwinger

From Wikipedia, the free encyclopedia

Julian Seymour Schwinger (February 12, 1918 -- July 16, 1994) was an American theoretical physicist. He formulated the theory of renormalization and posited a phenomenon of electron-positron pairs known as the Schwinger effect. He was jointly awarded the Nobel Prize in Physics in 1965 for his work on quantum electrodynamics (QED), along with Richard Feynman and Shinichiro Tomonaga.

Schwinger was born in New York City where he attended Townsend Harris High School and then the City College of New York as an undergraduate before transferring to Columbia University, where he received his B.A. in 1936 and his Ph.D. (overseen by I.I. Rabi) in 1939. He worked at the University of California, Berkeley (under J. Robert Oppenheimer) and was later appointed to a position at Purdue University.

During World War II Schwinger worked at the Radiation Laboratory at MIT, providing theoretical support for the development of radar. He tried applying his knowledge as a Nuclear Physicist to electromagnetic engineering problems, and arrived at results on nuclear scattering. Consequently, Schwinger began to apply his understanding of radiation to quantum physics.

After the war, Schwinger left Purdue for Harvard University, where he taught from 1945 to 1974. He married in 1947. During this time, he developed the concept of renormalization, which explained the Lamb shift in an electron's magnetic field. He also realized, in his study of particle physics, that neutrinos would come in multiple varieties, associated with leptons like the electron and muon, which was experimentally verified in recent years.

Having supervised more than seventy doctoral dissertations, Schwinger is known as one of the most prolific graduate advisors in physics. Four of his students won Nobel prizes: Roy Glauber, Benjamin Roy Mottelson, Sheldon Glashow and Walter Kohn (in chemistry).

In his later career, displeased with the complexity of other explanations of particle physics experiments, Schwinger developed source theory, which treats gravitons, photons, and other particles uniformly. Schwinger left Harvard in 1972 for a position the University of California, Los Angeles where he continued his work on source theory, until his death.

After 1989 Schwinger took a keen interest in the research of low-energy nuclear fusion reactions (AKA cold fusion). He wrote eight theory papers about it, including these [1] [2]. He resigned from the American Physical Society after their refusal to publish his papers. He felt that cold fusion research was being suppressed and academic freedom violated. He wrote: "The pressure for conformity is enormous. I have experienced it in editors’ rejection of submitted papers, based on venomous criticism of anonymous referees. The replacement of impartial reviewing by censorship will be the death of science." [3]

1 Schwinger and Feynman
2 See also
3 Further reading
4 External links

[edit] Schwinger and Feynman

As a famous physicist, Schwinger was often compared to another legendary physicist of his generation, Richard Feynman. Schwinger was more mathematically inclined and heavily favoured mathematical rigour in his way of doing physics, especially in the field of Quantum Field Theory. By contrast, Feynman was more intuitive and this showed in his Feynman diagram approach to QFT. Schwinger disliked Feynman diagrams to the point of banning them altogether in his class.

[edit] See also

[edit] Further reading

Mehra, Jagdish and Milton, Kimball A. Climbing the Mountain: the scientific biography of Julian Schwinger, Oxford University Press, 2000.
Milton, Kimball (2006-10-9). Julian Schwinger: Nuclear Physics, the Radiation Laboratory, Renormalized QED, Source Theory, and Beyond. arXiv.
Schweber, Sylvan S., QED and the men who made it : Dyson, Feynman, Schwinger, and Tomonaga. Princeton Univ. Press, 1994.