Julian Seymour Schwinger was born on February 12, 1918, in New York City. He attended the City College of New York as an undergraduate, and received his doctorate from Columbia University in 1939 where he studied under I.I. Rabi. He worked at the University of California, Berkeley 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.
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 1974 for a position at UCLA where he continued his work on source theory.
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 Sin-Itiro Tomonaga.
In addition to receiving the Nobel Prize, he was also awarded the first Einstein Prize (1951) and the U.S. National Medal of Science (1964).
Schwinger died on July 16, 1994.