Kimball A. Milton - Böcker

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.

Julian Schwinger was already the world’s leading nuclear theorist when he joined the Radiation Laboratory at MIT in 1943, at the ripe age of 25. Just 2 years earlier he had joined the faculty at Purdue, after a postdoc with OppenheimerinBerkeley,andgraduatestudyatColumbia. Anearlysemester at Wisconsin had con?rmed his penchant to work at night, so as not to have to interact with Breit and Wigner there. He was to perfect his iconoclastic 1 habits in his more than 2 years at the Rad Lab. Despite its deliberately misleading name, the Rad Lab was not involved in nuclear physics, which was imagined then by the educated public as a esoteric science without possible military application. Rather, the subject at hand was the perfection of radar, the beaming and re?ection of microwaves which had already saved Britain from the German onslaught. Here was a technology which won the war, rather than one that prematurely ended it, at a still incalculable cost. It was partly for that reason that Schwinger joined this e?ort, rather than what might have appeared to be the more natural project for his awesome talents, the development of nuclear weapons at Los Alamos. He had got a bit of a taste of that at the “Metallurgical Laboratory” in Chicago, and did not much like it. Perhaps more important for his decision to go to and stay at MIT during the war was its less regimented and isolated environment.

Julian Schwinger was already the world’s leading nuclear theorist when he joined the Radiation Laboratory at MIT in 1943, at the ripe age of 25. Just 2 years earlier he had joined the faculty at Purdue, after a postdoc with OppenheimerinBerkeley,andgraduatestudyatColumbia. Anearlysemester at Wisconsin had con?rmed his penchant to work at night, so as not to have to interact with Breit and Wigner there. He was to perfect his iconoclastic 1 habits in his more than 2 years at the Rad Lab. Despite its deliberately misleading name, the Rad Lab was not involved in nuclear physics, which was imagined then by the educated public as a esoteric science without possible military application. Rather, the subject at hand was the perfection of radar, the beaming and re?ection of microwaves which had already saved Britain from the German onslaught. Here was a technology which won the war, rather than one that prematurely ended it, at a still incalculable cost. It was partly for that reason that Schwinger joined this e?ort, rather than what might have appeared to be the more natural project for his awesome talents, the development of nuclear weapons at Los Alamos. He had got a bit of a taste of that at the “Metallurgical Laboratory” in Chicago, and did not much like it. Perhaps more important for his decision to go to and stay at MIT during the war was its less regimented and isolated environment.

The present volume comprehensively summarizes the late Julian Schwinger's work on the theory of electromagnetic radiation and its application to waveguides, transmission lines, accelerator physics and synchrotron radiation. The first part, written in textbook style, has grown out of lectures and manuscripts by Julian Schwinger prepared during the war at MIT's Radiation Laboratory, updated with material developed by Schwinger at UCLA in the 1970s and 1980s, and by Milton at the University of Oklahoma since 1994. The second part consists of reprints of more than 15 papers (some of them never published or available with very limited circulation) by Schwinger on these topics. This volume will be of great interest to physicists, electrical engineers and applied mathematicians whether they be students or seasoned professionals. A paperback study edition of the first part is available separately.

Julian Schwinger (1918-1994) was one of the giants of 20th Century science. He contributed to a broad range of topics in theoretical physics, ranging from classical electrodynamics to quantum mechanics, from nuclear physics through quantum electrodynamics to the general theory of quantum fields. Although his mathematical prowess was legendary, he was fundamentally a phenomenologist. He received many awards, including the first Einstein Prize in 1951, and the Nobel Prize in 1965, which he shared with Richard Feynman and Sin-itiro Tomonaga for the self-consistent formulation of quantum electrodynamics into a practical theory. His more than 70 doctoral students have played a decisive role in the development of science in the second half of this century.This important volume includes many of Schwinger's most important papers, on the above and other topics, such as the theory of angular momentum and the theory of many-body systems. The papers collected here continue to underlie much of the work done by theoretical physicists today.

In its simplest manifestation, the Casimir effect is a quantum force of attraction between two parallel uncharged conducting plates. More generally, it refers to the interaction — which may be either attractive or repulsive — between material bodies due to quantum fluctuations in whatever fields are relevant. It is a local version of the van der Waals force between molecules. Its sweep ranges from perhaps its being the origin of the cosmological constant to its being responsible for the confinement of quarks.This monograph develops the theory of such forces, based primarily on physically transparent Green's function techniques, and makes applications from quarks to the cosmos, as well as observable consequences in condensed matter systems. It is aimed at graduate students and researchers in theoretical physics, quantum field theory, and applied mathematics.

This review volume is intended to survey the field of quantum fluctuational phenomena induced by material bodies, which is commonly encompassed under the name of Casimir physics. H B G Casimir first discovered that zero-point fluctuations in the electromagnetic field caused an attractive force between closely separated metallic plates. Now — 75 years later — the field is burgeoning, with numerous experimental verifications and applications to practical devices starting to emerge.In this book, new ideas about Casimir physics are brought to bear on such diverse subjects as cosmology, where the Casimir energy may explain the dark energy that causes the cosmic repulsion, and nonstatic regimes, such as Casimir or quantum friction. Unsolved problems, including divergences in Casimir self-energies, the meaning of local energy densities in inhomogeneous backgrounds, and discrepancies between theory and experiment, are treated in some detail. It is hoped that this collection of papers will serve as an introduction to the field for newcomers to the subject, and that it will inspire a new burst of research into the nature of the quantum vacuum.