TY - BOOK AU - Toms,David J. TI - The Schwinger action principle and effective action T2 - Cambridge monographs on mathematical physics SN - 9780511585913 (ebook) AV - QC174.17.S32 T66 2007 U1 - 530.12 22 PY - 2007/// CY - Cambridge PB - Cambridge University Press KW - Schwinger action principle KW - Quantum theory KW - Mathematical physics N1 - Title from publisher's bibliographic system (viewed on 05 Oct 2015); 1. Action principle in classical mechanics -- 2. Action principle in classical field theory -- 3. Action principle in quantum theory -- 4. The effective action -- 5. Quantum statistical mechanics -- 6. Effective action at finite temperature -- 7. Further applications of the Schwinger action principle -- 8. General definition of the effective action -- App. 1. Mathematical appendices -- App. 2. Review of special relativity -- App. 3. Interaction picture N2 - This book, first published in 2007, is an introduction to the Schwinger action principle in quantum mechanics and quantum field theory, with applications to a variety of different models including Bose-Einstein condensation, the Casimir effect and trapped Fermi gases. The book begins with a brief review of the action principle in classical mechanics and classical field theory. It then moves on to quantum field theory, focusing on the effective action method. This is introduced as simply as possible by using the zero-point energy of the simple harmonic oscillator as the starting point. The book concludes with a more complete definition of the effective action, and demonstrates how the provisional definition used earlier is the first term in the systematic loop expansion. The renormalization of interacting scalar field theory is presented to two-loop order. This book will interest graduate students and researchers in theoretical physics who are familiar with quantum mechanics UR - https://doi.org/10.1017/CBO9780511585913 ER -