Schwinger's Quantum Action Principle

Professor Kimball Milton is the George Lynn Cross Research Professor of Physics at the University of Oklahoma. Kim Milton, a student of Julian Schwinger, studies in particular vacuum energy phenomena (the Casimir effect) in contexts ranging from cosmological through hadronic to condensed matter systems. He is the author, together with J Mehra of "Climbing the Mountain: The Scientific Biography of Julian Schwinger" Oxford University Press, 2000.

• Historical introduction.- Review of classical action principles.- Classical field theory - electrodynamics.- Quantum Action Principle.- Time-cycle or Schwinger-keldysh Formulation.- Relativistic Theory of Fields.- Nonrelativistic Source theory.- Concluding remarks.

"The main goal of this short book is to examine quantum action principles and, in particular, the Schwinger action principle. ... For anyone who is interested in a good but brief introduction to the subject, this monograph should be considered." (Paul F. Bracken, Mathematical Reviews, April, 2016)