Julian Seymour Schwinger (February 12, 1918 – July 16, 1994) was a
Nobel Prize winning
American theoretical physicist. He is best known for his work on the
theory of
quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order. Schwinger was a professor in the physics department at
UCLA.