Julian Schwinger ( 1918 - 1994 )

Julian Schwinger’s influence on Twentieth Century science is profound and pervasive. Of course, he is most famous for his renormalization theory of quantum electrodynamics, for which he shared the Nobel Prize with Richard Feynman and Sin-itiro Tomonaga. But although this triumph was undoubtedly his most heroic accomplishment, his legacy lives on chiefly through subtle and elegant work in classical electrodynamics, quantum variational principles, proper-time methods, quantum anomalies, dynamical mass generation, partial symmetry, and more. Starting as just a boy, he rapidly became the pre-eminent nuclear physicist in the late 1930s, led the theoretical development of radar technology at MIT during World War II, and then, soon after the war, conquered quantum electrodynamics, and became the leading quantum field theorist for two decades, before taking a more iconoclastic route during his last quarter century. Given his commanding stature in theoretical physics for decades it may seem puzzling why he is relatively unknown now to the educated public, even to many younger physicists, while Feynman is a cult figure with his photograph needing no more introduction than Einstein’s. This relative obscurity is even more remarkable, in view of the enormous number of eminent physicists, as well as other leaders in science and industry, who received their Ph.D.’s under Schwinger’s direction, while Feynman had but few. In part, the answer lies in Schwinger’s retiring nature and reserved demeanor. Science, research and teaching, were his life, and he detested the limelight. Generally, he was not close to his students, so few knew him well. He was a gracious