NOBEL LECTURES IN PHYSICS 1942-1962 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 INCLUDING PRESENTATION SPEECHES AND LAUREATES BIOGRAPHIES PHYSICS 1942-1962 b World Scientific b Singapore l New Jersey · London l Hong Kong I i Publishedfor the Nobel Foundation in 1998 by World Scientific Publishing Co. Pte. Ltd. PO Box 128, Farrer Road, Singapore 912805 USA office: Suite 1B, 1060 Main Street, River Edge, NJ 07661 UK office:57 Shelton Street, Covent Garden, London WC2H 9HE NOBEL LECTURES IN PHYSICS (1942-1962) All rights reserved. ISBN98 l-02-3403-1 Printed in Singapore 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 1901-1970, which were published in 1964-1972 through the following volumes: Physics 1901-1970 4 volumes Chemistry 1901-1970 4 volumes Physiology or Medicine 1901-1970 4 volumes Literature 1901-1967 1 volume Peace 1901-1970 3 volumes 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 Contents Foreword V 1942 (Prize not awarded) 1943 OTTO STERN 1944 ISIDOR ISAAC RABI Motivation 3 Account of Stem’s and Rabi’s works by E. Hulthén 5 The method of molecular rays, by O. Stern 8 Biography 0. Stern 17 Biography I. I. Rabi 20 1945 WOLFGANG PAULI Motivation 23 Presentation by I. Waller 25 Exclusion principle and quantum mechanics, by W. Pauli 27 Biography W. Pauli 44 1946 PERCY WILLIAMS BRIDGMAN Motivation 47 Presentation by A. E. Lindh 49 General survey of certain results in the field of high-pressure physics, by P. W. Bridgman 53 Biography P. W. Bridgman 71 1947 Sir EDWARD VICTOR APPLETON Motivation 73 Presentation by E. H&h&n 75 The ionosphere, by E. V. Appleton 79 Biography E. V. Appleton 87 VIII CONTENTS 1948 PATRICK MAYNARD STUART BLACKETT Motivation 91 Presentation by G. Ising 93 Cloud chamber researches in nuclear physics and cosmic radiation, by P. M. S. Blackett 97 Biography P. M. S. Blackctt 120 1949 HIDEKI YUKAWA Motivation 123 Presentation by I. Waller 125 Meson theory in its developments, by H.Yukawa 128 Biography H. Yukawa 135 1950 CECIL FRANK POWELL Motivation 137 Presentation by A. E. Lindh 139 The cosmic radiation, by C. F. Powell 144 Biography C. F. Powell 158 1951 Sir JOHN DOUGLAS COCKCROFT and ERNEST THOMAS SINTON WALTON Motivation 161 Presentation by I. Waller 163 Experiments on the interaction of high-speed nucleons with atomic nuclei, by J. D. Cockcroft 167 Biography J. D. Cockcroft 185 The artificial production of fast particles, by E. T. S. Walton 187 Biography E. T. S. Walton 195 1952 FELIX BLOCH and EDWARD MILLS PURCELL Motivation I97 Presentation by E. Hulthén I99 The principle of nuclear induction, by F. Bloch 203 Biography F. Bloch 217 Research in nuclear magnetism, by E. M. Purcell 219 Biography E. M. Purcell 232 CONTENTS IX 1953 FRITS ZERNIKE Motivation 235 Presentation by E. Hulthén 237 How I discovered phase contrast, by F. Zernike 239 Biography F. Zernike 247 1954 MAX BORN and WALTHER BOTHE Motivation 251 Presentation by I. Waller 253 The statistical interpretation of quantum mechanics, by M. Born 256 Biography M. Born 268 The coincidence method, by W. Bothe 271 Biography W. Bothe 277 1955 WILLIS EUGENE LAMB and POLYKARP KUSCH Motivation 281 Presentation by I. Waller 283 Fine structure of the hydrogen atom, by W. E. Lamb, Jr. 286 Biography W. E. Lamb, Jr. 296 The magnetic moment of the electron, by P. Kusch 298 Biography P. Kusch 311 1956 WILLIAM SHOCKLEY, JOHN BARDEEN and WALTER HOUSER BRATTAIN Motivation 313 Presentation by E. G. Rudberg 315 Semiconductor research leading to the point contact transistor, by J. Bardeen 318 Biography J. Bardeen 342 Transistor technology evokes new physics, by W. Shockley 344 Biography W. Shockley 375 Surface properties of semiconductors, by W. H. Brattain 377 Biography W. H. Brattain 385 1957 CHEN NING YANG and TSUNG DAO LEE Motivation 387 Presentation by O. B. Klein 389 X CONTENTS The law of parity conservation and other symmetry laws of physics, by C. N. Yang 393 Biography C. N. Yang 404 Weak interactions and nonconservation of parity, by T. D. Lee 406 Biography T. D. Lee 419 1958 PAVEL ALEKSEJEVI? EERENKOV, IL’JA MICHAJLOVI~ FRANK and IGOR'’ EVGEN’EVI? TAMM Motivation 421 Presentation by K. Siegbahn 423 Radiation of particles moving at a velocity exceeding that of light, and some of the possibilities for their use in experimental phyzics, by P. A. Cerenkov 426 Biography P. A. Cerenkov 441 Optics of light sources moving in refractive media, by I. M. Frank 442 Biography I. M. Frank 469 General characteristics of radiations emitted by systems moving with super-light velocities with some applications to plasma physics, by I. E. Tamm 470 Biography I. E. Tamm 483 1959 EMILIO GINO SEGRÈ and OWEN CHAMBERLAIN Motivation 485 Presentation by E. Hulthén 487 The early antiproton work, by O. Chamberlain 489 Biography O. Chamberlain 506 Properties of antinucleons, by E. G. Segrè 508 Biography E. G. Segrè 521 1960 DONALD ARTHUR GLASER Motivation 523 Presentation by K. Siegbahn 525 Elementary particles and bubble chambers, by D. A. Glaser 529 Biography D. A. Glaser 552 CONTENTS XI ROBERT HOFSTADTER and RUDOLF LUDWIG MÖSSBAUER Motivation 555 Presentation by I. Waller 557 The electron-scattering method and its application to the structure of nuclei and nucleons, by R. Hofstadter 560 Biography R. Hofstadter 582 Recoilless nuclear resonance absorption of gamma radiation, by R. L. Mijssbauer 584 Biography R. L. Mössbauer 602 1962 LEV DAVIDOVIC LANDAU Motivation 605 Presentation by I. Waller 607 Biography L. D. Landau 611 Name Index 613 Subject Index 620 Index of Biographies 621 Physics 1942 Prize not awarded. Physics 1943 and 1944 OTTO STERN [1943] << for his contribution to the development of the molecular ray method and his discovery of the magnetic moment of the proton >> ISIDOR ISAAC RABI [I944] « for his resonance method for recording the magnetic properties of atomic nuclei » Physics 1943 and 1944 The following account of Stern’s and Rabi’s works is by Professor E. Hulthén, Stockholm (Broadcast lecture, 10th December, 1944) There is a certain relation between electric and magnetic phenomena in that the magnetic field can generally be ascribed to the presence of electric cur- rents. It was in this way that the famous Ampère sought to trace magnetism back to rotary currents of electricity in the particles of matter, the atoms and molecules. This hypothesis has in fact been confirmed, inter alia by spec- troscopical investigations into light sources placed in very strong magnetic fields. However, certain difficulties arose when it came to accounting in de- tail for the influence of the magnetic field on the movement of electrons, which here represents the electric currents in the interior of the atom. For the electrons proved disinclined to obey the electrodynamic laws which have otherwise so brilliantly demonstrated their validity in, for instance, the field of electrotechnics. Inter alia, it seemed as if the small, freely moving atomic magnet in the source of light was only capable of assuming certain discrete local positions in relation to the direction of the applied field. I shall start, then, with a reference to an experiment which for the first time revealed this remarkable so-called directional or space-quantization effect. The experiment was carried out in Frankfurt in 1920 by Otto Stern and Walter Gerlach, and was arranged as follows: In a small electrically heated furnace, was bored a tiny hole, through which the vapour flowed into a high vacuum so as to form thereby an extremely thin beam of vapour. The molecules in this so-called atomic or molecular beam all fly forwards in the same direction without any appreciable collisions with one another, and they were registered by means of a detector, the design of which there is un- fortunately no time to describe here. On its way between the furnace and the detector the beam is affected by a non-homogeneous magnetic field, so that the atoms - if they really are magnetic - become unlinked in one direction or another, according to the position which their magnetic axles may assume in relation to the field. The classical conception was that the thin and clear-cut beam would consequently expand into a diffuse beam, but in actual fact the opposite proved to be the case. The two experimenters found that the beam divided up into a number of relatively still sharply defined beams, each 6 PHYSICS 1943 AND 1944 corresponding to one of the just mentioned discrete positional directions of the atoms in relation to the field. This confirmed the space-quantization hypothesis. Moreover, the experiment rendered it possible to estimate the magnetic factors of the electron, which proved to be in close accord with the universal magnetic unit, the so-called « Bohr’s magneton ».