NOBEL LECTURES I NCLUDING P RESENTATION S PEECHES AND LAUREATES' BIOGRAPHIES PHYSICS 1971-1980 E DITOR STIG LUNDQVIST Published for the Nobel Foundation in 1992 by World Scientific Publishing Co. Pte. Ltd. P O Box 128, Farrer Road, Singapore 9128 USA Office: Suite 1B, 1060 Main Street, River Edge, NJ 07661 UK office: 73 Lynton Mead, Totteridge, London N20 8DH First published 1992 First reprint 1994 NOBEL LECTURES IN PHYSICS (1971-1980) All rights reserved ISBN 981-02-0726-3 981-02-0727-1 (pbk) Printed in Singapore. NOBEL LECTURES I NCLUDING P RESENTATION S PEECHES A ND L AUREATES B IOGRAPHIES PHYSICS CHEMISTRY PHYSIOLOGY OR MEDICINE LITERATURE PEACE ECONOMIC SCIENCES NOBEL LECTURES IN PHYSICS 1971-1980 Foreword Since 1901 the Nobel Foundation has published annually “Les Prix Nobel” with reports from the Nobel Award Ceremonies in Stockholm and Oslo as well as the biographies and Nobel lectures of the laureates. In order to make the lectures available to people with special interests in the different prize fields the Foundation gave Elsevier Publishing Company the right to publish in English the lectures for 1910-1970, which were published in 1964-1972 through the following volumes: Physics 1901-1970 4 vols. Chemistry 1901-1970 4 vols. Physiology or Medicine 1901-1970 4 vols. Literature 1910-1967 1 vol. Peace 1910-1970 3 vols. Elsevier decided later not to continue the Nobel project. It is therefore with great satisfaction that the Nobel Foundation has given World Scientific Publishing Company the right to bring the series up to date. The Nobel Foundation is very pleased that the intellectual and spiritual message to the world laid down in the laureates’ lectures will, thanks to the efforts of World Scientific, reach new readers all over the world. Lars Gyllensten Stig Ramel Chairman of the Board Executive Director Stockholm, June 1991 vii PREFACE The Nobel Foundation publishes annually the proceedings of the year’s Prize ceremonies in a volume called Les Prix Nobel. It contains the speeches given at the prize ceremony, the autobiography of each laureate as well as the Nobel Lecture. These books contain much material of great interest to the scientific community. However, they are printed only in a small number of copies, very few scientists even know that they exist and there is no advertisement. From 1992 the material is now becoming available through a deal between the Nobel Foundation and World Scientific to publish the material from the 70’s and the 80’s in a series of volumes. This volume contains the materials in physics for the period 1970-1979. The contents in this volume are not identical with the original in Les Prix Nobel. We have written to all the physics laureates and let them modify and update the material. The reader may be surprised about the very short speeches of presentation. The reason is that only a few minutes are allotted to these speeches which did not permit any description of the discovery. Stig Lundqvist ix CONTENTS Foreword V Preface vii 1971 DENIS GABOR 1 Presentation by Erik Ingelstam 3 Biography of Denis Gabor 7 Holography, 1948 -1971 11 1972 JOHN BARDEEN, LEON N COOPER and J ROBERT SCHRIEFFER 45 Presentation by Stig Lundqvist 47 Biography of John Bardeen 51 Electron-Phonon Interactions and Superconductivity 54 Biography of Leon N Cooper 71 Microscopic Quantum Interference Effects in the Theory of Superconductivity 73 Biography of J Robert Schrieffer 95 Macroscopic Quantum Phenomena from Pairing in Superconductors 97 1973 LEO ESAKI, IVAR GIAEVER and BRIAN D JOSEPHSON 109 Presentation by Stig Lundqvist 111 Biography of Leo Esaki 115 Long Journey into Tunneling 116 Biography of Ivar Giaever 135 Electron Tunneling and Superconductivity 137 Biography of Brian D Josephson 155 The Discovery of Tunnelling Supercurrents 157 x Contents 1974 MARTIN RYLE and ANTONY HEWISH 165 Presentation by Hans Wilhelmsson 167 Biography of Antony Hewish 171 Pulsars and High Density Physics 174 Biography of Martin Ryle 185 Radio Telescopes of Large Resolving Power 187 1975 AAGE BOHR, BEN R MOTTELSON and JAMES RAINWATER 205 Presentation by Sven Johansson 207 Biography of Aage Bohr 211 Rotational Motion in Nuclei 213 Biography of Ben R Mottelson 235 Elementary Modes of Excitation in the Nucleus 236 Biography of James Rainwater 257 Background for the Spheroidal Nuclear Model Proposal 259 1976 BURTON RICHTER and SAMUEL C C TING 271 Presentation by Gösta Ekspong 273 Biography of Burton Richter 277 From the Psi to Charm -The Experiments of 1975 and 1976 281 Biography of Samuel Chao Chung Ting 313 The Discovery of the J Particle: A Personal Collection 316 1977 PHILIP W ANDERSON, NEVILL F MOTT and JOHN H VAN VLECK 345 Presentation by Per-Olov Löwdin 347 Biography of John Hasbrouck Van Vleck 351 Quantum Mechanics : The Key to Understanding Magnetism 353 Biography of Philip W Anderson 371 Local Moments and Localized States 376 Biography of Nevill Francis Mott 401 Electrons in Glass 403 1978 PETER LEONIDOVITCH KAPITZA, ARNO A PENZIAS and ROBERT W WILSON 415 Presentation by Lamek Hulthén 417 xi Biography of Peter Leonidovitch Kapitza 421 Plasma and the Controlled Thermonuclear Reaction 424 Biography of Arno A Penzias 439 The Origin of Elements 444 Biography of Robert W Wilson 459 The Cosmic Microwave Background Radiation 463 1979 SHELDON L GLASHOW, ABDUS SALAM and STEVEN WEINBERG 485 Presentation by Bengt Nagel 487 Biography of Sheldon Lee Glashow 491 Towards a Unified Theory - Threads in a Tapestry 494 Biography of Abdus Salam 507 Gauge Unification of Fundamental Forces 513 Biography of Steven Weinberg 541 Conceptual Foundations of the Unified Theory of Weak and Electromagnetic Interactions 543 1980 JAMES W CRONIN and VAL L FITCH 561 Presentation by Costa Ekspong 563 Biography of James W Cronin 567 CP Symmetry Violation - The Search for Its Origin 570 Biography of Val Logsdon Fitch 591 The Discovery of Charge-Conjugation Parity Symmetry 594 Physics 1971 DENNIS GABOR for his invention and development of the holographic method THE NOBEL PRIZE FOR PHYSICS Speech by professor ERIK INGELSTAM of the Royal Academy of Sciences Translation Your Majesty, Your Royal Highnesses, Ladies and Gentlemen, Our five senses give us knowledge of our surroundings, and nature herself has many available resources. The most obvious is light which gives us the possibility to see and to be pleased by colour and shape. Sound conveys the speech with which we communicate with each other and it also allows us to experience the tone-world of music. Light and sound are wave motions which give us information not only on the sources from which they originate, but also on the bodies through which they pass, and against which they are reflected or deflected. But light and sound are only two examples of waves which carry information, and they cover only very small parts of the electromagnetic and acoustic spectra to which our eyes and ears are sensitive. Physicists and technologists are working continuously to improve and broaden the methods and instruments which give us knowledge about waves which lie outside our direct perception capacity. The electron microscope re- solves structures which are a thousand times smaller than the wavelength of visible light. The photographic plate preserves for us a picture of a fleeting moment, which perhaps we may make use of over a long time period for measurements, or it transforms a wave-field of heat rays, X rays, or electron rays to a visible image. And yet, important information about the object is missing in a photo- graphic image. This is a problem which has been a key one for Dennis Gabor during his work on information theory. Because the image reproduces only the effect of the intensity of the incident wave-field, not its nature. The other characteristic quantity of the waves, phase, is lost and thereby the three dimensional geometry. The phase depends upon from which direction the wave is coming and how far it has travelled from the object to be imaged. Gabor found the solution to the problem of how one can retain a wave-field with its phase on a photographic plate. A part of the wave-field, upon which the object has not had an effect, namely a reference wave, is allowed to fall on the plate together with the wave-field from the object. These two fields are superimposed upon one another, they interfere, and give the strongest il- lumination where they have the same phase, the weakest where they ex- tinguish each other by having the opposite phase. Gabor called this plate a hologram, from the Greek holos, which means whole or complete, since the plate contains the whole information. This information is stored in the plate in a coded form. When the hologram is irradiated only with the reference wave, this wave is deflected in the hologram structure, and the original ob- 4 Physics 1971 ject’s field is reconstructed. The result is a three dimensional image. Gabor originally thought of using the principle to make an electron micro- scope image in two steps: first to register an object’s field with electron rays in a hologram, and then to reconstruct this with visible light to make a three dimensional image with high resolution. But suitable electron sources for this were not available, and also for other technical reasons the idea could not be tested. However, through successful experiments with light Gabor could show that the principle was correct. In three papers from 1948 to 1951 he attained an exact analysis of the method, and his equations, even today, con- tain all the necessary information. Holography, as this area of science is called, made its break-through when the tool, which had so far been missing, became available, namely the laser as a light source.