Schwinger's Quantum Action Principle

Schwinger's Quantum Action Principle
Author: Kimball A. Milton
Publisher: Springer
Total Pages: 122
Release: 2015-06-12
Genre: Science
ISBN: 331920128X

Starting from the earlier notions of stationary action principles, these tutorial notes shows how Schwinger’s Quantum Action Principle descended from Dirac’s formulation, which independently led Feynman to his path-integral formulation of quantum mechanics. Part I brings out in more detail the connection between the two formulations, and applications are discussed. Then, the Keldysh-Schwinger time-cycle method of extracting matrix elements is described. Part II will discuss the variational formulation of quantum electrodynamics and the development of source theory.

Schwinger's Quantum Action Principle

Schwinger's Quantum Action Principle
Author: Kimball A. Milton
Publisher:
Total Pages: 122
Release: 2015
Genre: Mathematical physics
ISBN: 9783319201290

Starting from the earlier notions of stationary action principles, these tutorial notes shows how Schwinger's Quantum Action Principle descended from Dirac's formulation, which independently led Feynman to his path-integral formulation of quantum mechanics. Part I brings out in more detail the connection between the two formulations, and applications are discussed. Then, the Keldysh-Schwinger time-cycle method of extracting matrix elements is described. Part II will discuss the variational formulation of quantum electrodynamics and the development of source theory.

The Development of the Action Principle

The Development of the Action Principle
Author: Walter Dittrich
Publisher: Springer Nature
Total Pages: 141
Release: 2021-05-29
Genre: Science
ISBN: 3030691055

This book describes the historical development of the principle of stationary action from the 17th to the 20th centuries. Reference is made to the most important contributors to this topic, in particular Bernoullis, Leibniz, Euler, Lagrange and Laplace. The leading theme is how the action principle is applied to problems in classical physics such as hydrodynamics, electrodynamics and gravity, extending also to the modern formulation of quantum mechanics and quantum field theory, especially quantum electrodynamics. A critical analysis of operator versus c-number field theory is given. The book contains many worked examples. In particular, the term "vacuum" is scrutinized.The book is aimed primarily at actively working researchers, graduate students and historians interested in the philosophical interpretation and evolution of physics; in particular, in understanding the action principle and its application to a wide range of natural phenomena.

A Quantum Legacy

A Quantum Legacy
Author: Julian Schwinger
Publisher: World Scientific
Total Pages: 812
Release: 2000
Genre: Science
ISBN: 9789810240066

Julian Schwinger (1918-94) contributed to a broad range of topics in theoretical physics, from classical electrodynamics to quantum mechanics. This volume includes many of his most important papers.

Quantum Statistical Field Theory

Quantum Statistical Field Theory
Author: Norman J. M. Horing
Publisher: Oxford University Press
Total Pages: 453
Release: 2017
Genre: Science
ISBN: 0198791941

The methods of coupled quantum field theory, which have played a major role in the extensive development of nonrelativistic quantum many-particle theory and condensed matter physics, are at the core of this book.

Classical Electrodynamics

Classical Electrodynamics
Author: Julian Schwinger
Publisher: CRC Press
Total Pages: 592
Release: 2019-05-20
Genre: Science
ISBN: 0429972091

Classical Electrodynamics captures Schwinger's inimitable lecturing style, in which everything flows inexorably from what has gone before. Novel elements of the approach include the immediate inference of Maxwell's equations from Coulomb's law and (Galilean) relativity, the use of action and stationary principles, the central role of Green's functions both in statics and dynamics, and, throughout, the integration of mathematics and physics. Thus, physical problems in electrostatics are used to develop the properties of Bessel functions and spherical harmonics. The latter portion of the book is devoted to radiation, with rather complete treatments of synchrotron radiation and diffraction, and the formulation of the mode decomposition for waveguides and scattering. Consequently, the book provides the student with a thorough grounding in electrodynamics in particular, and in classical field theory in general, subjects with enormous practical applications, and which are essential prerequisites for the study of quantum field theory.An essential resource for both physicists and their students, the book includes a ?Reader's Guide,? which describes the major themes in each chapter, suggests a possible path through the book, and identifies topics for inclusion in, and exclusion from, a given course, depending on the instructor's preference. Carefully constructed problems complement the material of the text, and introduce new topics. The book should be of great value to all physicists, from first-year graduate students to senior researchers, and to all those interested in electrodynamics, field theory, and mathematical physics.The text for the graduate classical electrodynamics course was left unfinished upon Julian Schwinger's death in 1994, but was completed by his coauthors, who have brilliantly recreated the excitement of Schwinger's novel approach.

The Principle of Least Action

The Principle of Least Action
Author: Alberto G. Rojo
Publisher: Cambridge University Press
Total Pages: 269
Release: 2018-03-29
Genre: Mathematics
ISBN: 0521869021

This text brings history and the key fields of physics together to present a unique technical discussion of the principles of least action.

Quantum Mechanics

Quantum Mechanics
Author: Julian Schwinger
Publisher: Springer Science & Business Media
Total Pages: 488
Release: 2013-06-29
Genre: Science
ISBN: 3662045893

A unique legacy, these lecture notes of Schwinger’s course held at the University of California at Los Angeles were carefully edited by his former collaborator Berthold-Georg Englert and constitute both a self-contained textbook on quantum mechanics and an indispensable source of reference on this fundamental subject by one of the foremost thinkers of twentieth century physics.

Climbing the Mountain

Climbing the Mountain
Author: K. A. Milton
Publisher:
Total Pages: 726
Release: 2000
Genre: Physicists
ISBN: 9780198527459

Julian Schwinger was one of the leading theoretical physicists of the twentieth century. His contributions are as important, and as pervasive, as those of Richard Feynman, with whom (and with Sin-itiro Tomonaga) he shared the 1965 Nobel Prize for Physics. Yet, while Feynman is universallyrecognized as a cultural icon, Schwinger is little known even to many within the physics community. In his youth, Julian Schwinger was a nuclear physicist, turning to classical electrodynamics after World War II. In the years after the war, he was the first to renormalize quantum electrodynamics.Subsequently, he presented the most complete formulation of quantum field theory and laid the foundations for the electroweak synthesis of Glashow, Weinberg, and Salam, and he made fundamental contributions to the theory of nuclear magnetic resonance, to many-body theory, and to quantum optics. Hedeveloped a unique approach to quantum mechanics, measurement algebra, and a general quantum action principle. His discoveries include 'Feynman's' parameters and 'Glauber's' coherent states; in later years he also developed an alternative to operator field theory which he called Source Theory,reflecting his profound phenomenological bent. His late work on the Thomas-Fermi model of atoms and on the Casimir effect continues to be an inspiration to a new generation of physicists. This biography describes the many strands of his research life, while tracing the personal life of this privateand gentle genius.

Feynman's Thesis

Feynman's Thesis
Author: Richard Phillips Feynman
Publisher: World Scientific
Total Pages: 142
Release: 2005
Genre: Science
ISBN: 9812563660

Richard Feynman's never previously published doctoral thesis formed the heart of much of his brilliant and profound work in theoretical physics. Entitled ?The Principle of Least Action in Quantum Mechanics," its original motive was to quantize the classical action-at-a-distance electrodynamics. Because that theory adopted an overall space?time viewpoint, the classical Hamiltonian approach used in the conventional formulations of quantum theory could not be used, so Feynman turned to the Lagrangian function and the principle of least action as his points of departure.The result was the path integral approach, which satisfied ? and transcended ? its original motivation, and has enjoyed great success in renormalized quantum field theory, including the derivation of the ubiquitous Feynman diagrams for elementary particles. Path integrals have many other applications, including atomic, molecular, and nuclear scattering, statistical mechanics, quantum liquids and solids, Brownian motion, and noise theory. It also sheds new light on fundamental issues like the interpretation of quantum theory because of its new overall space?time viewpoint.The present volume includes Feynman's Princeton thesis, the related review article ?Space?Time Approach to Non-Relativistic Quantum Mechanics? [Reviews of Modern Physics 20 (1948), 367?387], Paul Dirac's seminal paper ?The Lagrangian in Quantum Mechanics'' [Physikalische Zeitschrift der Sowjetunion, Band 3, Heft 1 (1933)], and an introduction by Laurie M Brown.