Description: This classic work presents the main results and calculational procedures of quantum electrodynamics in a simple and straightforward way. Designed for the student of experimental physics who does not intend to take more advanced graduate courses in theoretical physics, the material consists of notes on the third of a threesemester course given at the California Institute of Technology. Điện động lực học lượng tử (Quantum electrodynamics) Trong vật lý hạt, điện động lực học lượng tử là lý thuyết trường lượng tử tương đối tính của điện động lực học. Về cơ bản, nó miêu tả cách ánh sáng và vật chất tương tác với nhau và là lý thuyết đầu tiên kết hợp được các tính chất của cơ học lượng tử và thuyết tương đối hẹp
ADVANCED BOOK CLASSICS David Pines, Series Editor Anderson, P.W., Baric Notions of Condensed Matter Physics Bethe H and Jackiw, R., Intermediate Q u a n ~ mMechanics, Third Edition Feynman, R., Photon-Hadron Interactions Feynman, R., Quantum Electrodynamics Feynman, R., Statistical Mechanics Feynman, R., The Theory of Ftrndamenral Processes Norieres, P*,Theory of Interacting Fermi System Pines, D., The Many-Body Problem Quigg, C., Gauge Theories of the Strong, Weak,and Electromagnetic Interactions RICHARD FEYNMAN late, California Institute of Ethnology Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks Where those designations appear in this book and Perseus Publishing was aware of a trademark claim, the designatians have been printed in initial capital letters All rights reserved No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, elecmnic, mechanical, photncopying, recording, or otherwise, without the prior written permission of the publisher Printed in the United States af America Westview Press is a member ofthe Perseus Books Group Cover design by Suzanne Heiser Editor's Foreword Addison-Wesley's Frontiers in Physics series has, since 1961, made it possible for leading physicists to communicate in coherent fashion their views of recent developments in the most exciting and active fields of physics-without having to devote the time and energy required to prepare a formal review or monograph Indeed, throughout its nearly forty-year existence, the series has emphasized informality in both style and content, as well as pedagogical clarity Over time, it was expected that these informal accounts would be replaced by more formal counterparts-textbooks or monographs-as the cutting-edge topics they treated gradually became integrated into the body of physics knowledge and reader interest dwindled However, this has not proven to be the case for a number of the volumes in the series: Many works have remained in print on an on-demand basis, while others have such intrinsic value that the physics community has urged us to extend their life span The Advanced Book Classics series has been designed to meet this demand It will keep in print those volumes in Frmliers in Physics or its sister series, Lecture Notes and Suppkments in Physics, that continue to provide a unique account of a topic of lasting interest And through a sizable printing, these classics will be made available at a comparatively modest cost to the reader These lecture notes on Richard Ft;ynnran8sCaltech course on Quantum Electrodynamics were first published in 1961, as part of the first group of lecture notelreprint volumes to be included in the Frontiers in Physics series As is the case with all of the Feynman lecture note volumes, the presentation in this work reflects his deep physical insight, the freshness and originality of his approach to quantum electrodynamics,and the overall pedagogical wizardry of Richard Feynman Taken together with the reprints included here of vi EDITOR" SFOREWQRD Feynman's seminal papers on the space-time approach to quantum electrodynamics and the theon, of positrons, the lecture notes provide beginning students and experienced researchers alike with an invaluable introduction to quantum electrodynamics and to Feynman's highly original approach to the topic Bavid Pines Idrbana, Elf inois December 997 Preface The text material herein constitutes notes on the third of a three-semester course in quantum mechanics given at the California Institute of Technology in 1953 Actually, some questions involving the interaction of light and matter were discussed during the preceding semester These are also included, as the first six lectures The relativistic theory begins in the seventh lecture The aim was to present the main results and calculational procedures of quantum electrodynamics in as simple and straightfaward a way as possible Many of the students working for degrees in experimental physics did not intend to take more advanced graduate courses in theoretical physics The course was designed with their needs in mind It was hoped that they would learn how one obtains the various cross sections for photon processes which are so important in the design of high-energy experiments, such as with the synchrotron at Cal Tech For this reason little attention is given to many aspects of quantum electrodynamics which would be of use for theoretical physicists tackling the more complicated problems of the interaction of pions and nucleons That is, the relations among the many different formulations of quantum electrodynamics, including operator representations of fields, explicit discussion of properties of the S matrix, etc., are not included These were available in a more advanced course in quantum field theory Nevertheless, this course is complete in itself, in much the way that a course dealing with Newton's laws can be a complete discussion of mechanics in a physical sense although topics such as least action or Hamilton's equations are omitted The attempt to teach elementary quantum mechanics and quantum electrodynamics together in just one year was an experiment It was based on the viii PREFACE idea that, as new fields of physics are opened up, students must work their way further back, to earlier stages of the educational program The first two terms were the usual quantum mechanical course using Schiff (McGraw-Hill) as a main reference (omitting Chapters X, XII, XIII, and XIV, relating to quantum electrodynamics) However, in order to ease the transition to the latter part of the course, the theory of propagation and potential scattering was developed in detail in the way outlined in Eqs 15-3 to 15-5 One other unusual point was made, namely, that the nonrelativistic Pauli equation could be written as on page of the notes The experiment was unsuccessful The total material was too much for one year, and much of the material in these notes is now given after a full year graduate course in quantum mechanics The notes were originally taken by A R Hibbs They have been edited and corrected by H T Yura and E R Huggins R R FEWMAN Pasadena, California November 1961 The publisher wishes to acknowledge the assistance of the American Physical Society in the preparation of this volume, specifically their permission to reprint the three articles from the Physical Review Contents Editor's Foreword Preface Interaction of Light with Matter-auantum Electrodynamics Discussion of Fermi" mehod Laws of Quantum electrodynamics RCsumC of the Principles and Results of Special Relativity Solution of the Maxwell equation in empq space Relativistic partide mechanics Ref a t i ~ s t i cWave Equation Units Ktein-Gcrrdon, Pauli, and Dirac equations Alpbra of the y matrices kuivalence tramformation Relativistic invariance Hamiltonian form of the Dirac equation Nonrelativistic approximation to the Dirac equation Solution of rhe Dirac huation for a Free Particle Defirtieion of the spin of a moving elecrron Norrnalizatian af the wave functions Methods of obtaining matrix elements Intepretation of negative energy states P o t e n ~ aProblems l Itn, Quantum Eleetradynamics Pair creation and annihilation Consewation of energy The propagation kernel Use of the kernel K, ( , l ) Transition probablility Scattering af an electron from a coulomb potenrial Galccllation of the propagation kernel for a free particle Momentum repreenration ... of Richard Feynman Taken together with the reprints included here of vi EDITOR" SFOREWQRD Feynman' s seminal papers on the space-time approach to quantum electrodynamics and the theon, of positrons,... i s the R"A1embertian operatar Xn four-vector notation, &is e w a tion has the solution V = A exp (-ipp xp), where p p p p = m2.Then, since there results The apparent impossibflity of negative... Chsed-loop processes, vacuum polarization Scattering of light by a potential Padi Principle and the Dirac Equation Replcints Summary of Numerical Factors for Transition Probabilities, Phys Rev,,