Shift to Quantum Electrodynamics
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Charles Hard Townes (1915–2015)
ARTICLE-IN-A-BOX Charles Hard Townes (1915–2015) C H Townes shared the Nobel Prize in 1964 for the concept of the laser and the earlier realization of the concept at microwave frequencies, called the maser. He passed away in January of this year, six months short of his hundredth birthday. A cursory look at the archives shows a paper as late as 2011 – ‘The Dust Distribution Immediately Surrounding V Hydrae’, a contribution to infrared astronomy. To get a feel for the range in time and field, his 1936 masters thesis was based on repairing a non-functional van de Graaf accelerator at Duke University in 1936! For his PhD at the California Institute of Technology, he measured the spin of the nucleus of carbon-13 using isotope separation and high resolution spectroscopy. Smythe, his thesis supervisor was writing a comprehensive text on electromagnetism, and Townes solved every problem in it – it must have stood him in good stead in what followed. In 1939, even a star student like him did not get an academic job. The industrial job he took set him on his lifetime course. This was at the legendary Bell Telephone Laboratories, the research wing of AT&T, the company which set up and ran the first – and then the best – telephone system in the world. He was initially given a lot of freedom to work with different research groups. During the Second World War, he worked in a group developing a radar based system for guiding bombs. But his goal was always physics research. After the War, Bell Labs, somewhat reluctantly, let him pursue microwave spectroscopy, on the basis of a technical report he wrote suggesting that molecules might serve as circuit elements at high frequencies which were important for communication. -
The Physical Tourist Physics and New York City
Phys. perspect. 5 (2003) 87–121 © Birkha¨user Verlag, Basel, 2003 1422–6944/05/010087–35 The Physical Tourist Physics and New York City Benjamin Bederson* I discuss the contributions of physicists who have lived and worked in New York City within the context of the high schools, colleges, universities, and other institutions with which they were and are associated. I close with a walking tour of major sites of interest in Manhattan. Key words: Thomas A. Edison; Nikola Tesla; Michael I. Pupin; Hall of Fame for GreatAmericans;AlbertEinstein;OttoStern;HenryGoldman;J.RobertOppenheimer; Richard P. Feynman; Julian Schwinger; Isidor I. Rabi; Bronx High School of Science; StuyvesantHighSchool;TownsendHarrisHighSchool;NewYorkAcademyofSciences; Andrei Sakharov; Fordham University; Victor F. Hess; Cooper Union; Peter Cooper; City University of New York; City College; Brooklyn College; Melba Phillips; Hunter College; Rosalyn Yalow; Queens College; Lehman College; New York University; Courant Institute of Mathematical Sciences; Samuel F.B. Morse; John W. Draper; Columbia University; Polytechnic University; Manhattan Project; American Museum of Natural History; Rockefeller University; New York Public Library. Introduction When I was approached by the editors of Physics in Perspecti6e to prepare an article on New York City for The Physical Tourist section, I was happy to do so. I have been a New Yorker all my life, except for short-term stays elsewhere on sabbatical leaves and other visits. My professional life developed in New York, and I married and raised my family in New York and its environs. Accordingly, writing such an article seemed a natural thing to do. About halfway through its preparation, however, the attack on the World Trade Center took place. -
Wolfgang Pauli Niels Bohr Paul Dirac Max Planck Richard Feynman
Wolfgang Pauli Niels Bohr Paul Dirac Max Planck Richard Feynman Louis de Broglie Norman Ramsey Willis Lamb Otto Stern Werner Heisenberg Walther Gerlach Ernest Rutherford Satyendranath Bose Max Born Erwin Schrödinger Eugene Wigner Arnold Sommerfeld Julian Schwinger David Bohm Enrico Fermi Albert Einstein Where discovery meets practice Center for Integrated Quantum Science and Technology IQ ST in Baden-Württemberg . Introduction “But I do not wish to be forced into abandoning strict These two quotes by Albert Einstein not only express his well more securely, develop new types of computer or construct highly causality without having defended it quite differently known aversion to quantum theory, they also come from two quite accurate measuring equipment. than I have so far. The idea that an electron exposed to a different periods of his life. The first is from a letter dated 19 April Thus quantum theory extends beyond the field of physics into other 1924 to Max Born regarding the latter’s statistical interpretation of areas, e.g. mathematics, engineering, chemistry, and even biology. beam freely chooses the moment and direction in which quantum mechanics. The second is from Einstein’s last lecture as Let us look at a few examples which illustrate this. The field of crypt it wants to move is unbearable to me. If that is the case, part of a series of classes by the American physicist John Archibald ography uses number theory, which constitutes a subdiscipline of then I would rather be a cobbler or a casino employee Wheeler in 1954 at Princeton. pure mathematics. Producing a quantum computer with new types than a physicist.” The realization that, in the quantum world, objects only exist when of gates on the basis of the superposition principle from quantum they are measured – and this is what is behind the moon/mouse mechanics requires the involvement of engineering. -
Turning Point in the Development of Quantum Mechanics and the Early Years of the Mossbauer Effect*
Fermi National Accelerator Laboratory FERMILAB-Conf-76/87-THY October 1976 A TURNING POINT IN THE DEVELOPMENT OF QUANTUM MECHANICS AND THE EARLY YEARS OF THE MOSSBAUER EFFECT* Harry J. Lipkin' Weizmann Institute of Science, Rehovot, Israel Argonne National Laboratory, Argonne, Illinois 60^39 Fermi National Accelerator Laboratory"; Batavia, Illinois 60S10 It is interesting to hear about the exciting early days recalled by Professors Wigner and Wick. I learned quantum theory at a later period, which might be called a turning point in its development, when the general attitude toward quantum mechanics and the study of physics was very different from what it is today. As an undergraduate student in electrical engineering in 19^0 in the United States I found a certain disagreement between the faculty and the students about the "relevance'- of the curriculum. Students thought a k-year course in electrical engineering should include more electronics than a one-semester 3-hour course. But the establishment emphasized the study of power machinery and power transmission because 95'/° of their graduates would eventually get jobs in power. Electronics, they said, was fun for students who were radio hams but useless on the job market. Students at that time did not have today's attitudes and did not stage massive demonstrations and protests against the curriculum. Instead a few of us who wished to learn more interesting things satisfied all the requirements of the engineering school and spent as much extra time as possible listening to fascinating courses in the physics building. There we had the opportunity to listen to two recently-arrived Europeans, Bruno Rossi and Hans Bethe. -
Laser Spectroscopy to Resolve Hyperfine Structure of Rubidium
Laser spectroscopy to resolve hyperfine structure of rubidium Hannah Saddler, Adam Egbert, and Will Weigand (Dated: 12 November 2015) This experiment had two main goals: to create an absorption spectrum for rubidium using the technique of absorption spectroscopy and to resolve the hyperfine structures for the two rubidium isotopes using saturation absorption spectroscopy. The absorption spectrum was used to determine the frequency difference between the ground state and first excited state for both isotopes. The calculated frequency difference was 6950 MHz ± 90 MHz for rubidium 87 and 3060 MHz ± 60 MHz for rubidium 85. Both values agree with the literature values. The hyperfine structure for rubidium 87 was able to be resolved using this experimental setup. The energy differences were determined to be 260 MHz ± 10 MHz and 150 MHz ± 10 Mhz MHz. The hyperfine structure for rubidium 85 was unable to be resolved using this experimental setup. Additionally the theory of doppler broadening was used to make measurements of the full width half maximum. These values were used to calculate a temperature of 310K ± 40 K which makes sense because the experiments were performed at room temperature. I. INTRODUCTION in the theory section and how they were manipulated and used to derive the results from the recorded data. Addi- tionally there is an explanation of experimental error and The era of modern spectroscopy began with the in- uncertainty associated the results. Section V is a conclu- vention of the laser. The word laser was originally an sion that ties the results of the experiment we performed acronym that stood for light amplification by stimulated to the usefulness of the technique of laser spectroscopy. -
SHELDON LEE GLASHOW Lyman Laboratory of Physics Harvard University Cambridge, Mass., USA
TOWARDS A UNIFIED THEORY - THREADS IN A TAPESTRY Nobel Lecture, 8 December, 1979 by SHELDON LEE GLASHOW Lyman Laboratory of Physics Harvard University Cambridge, Mass., USA INTRODUCTION In 1956, when I began doing theoretical physics, the study of elementary particles was like a patchwork quilt. Electrodynamics, weak interactions, and strong interactions were clearly separate disciplines, separately taught and separately studied. There was no coherent theory that described them all. Developments such as the observation of parity violation, the successes of quantum electrodynamics, the discovery of hadron resonances and the appearance of strangeness were well-defined parts of the picture, but they could not be easily fitted together. Things have changed. Today we have what has been called a “standard theory” of elementary particle physics in which strong, weak, and electro- magnetic interactions all arise from a local symmetry principle. It is, in a sense, a complete and apparently correct theory, offering a qualitative description of all particle phenomena and precise quantitative predictions in many instances. There is no experimental data that contradicts the theory. In principle, if not yet in practice, all experimental data can be expressed in terms of a small number of “fundamental” masses and cou- pling constants. The theory we now have is an integral work of art: the patchwork quilt has become a tapestry. Tapestries are made by many artisans working together. The contribu- tions of separate workers cannot be discerned in the completed work, and the loose and false threads have been covered over. So it is in our picture of particle physics. Part of the picture is the unification of weak and electromagnetic interactions and the prediction of neutral currents, now being celebrated by the award of the Nobel Prize. -
Laser Spectroscopy Experiments
Hyperfine Spectrum of Rubidium: laser spectroscopy experiments Physics 480W (Dated: Sp19 Paper #4) I. OBJECTIVES FOR THESE EXPERIMENTS We wish to use the technique of absorption spec- troscopy to probe and detect the energy level structure of atomic Rubidium, Rb I, whose ground state is split by a tiny amount on account of nuclear magnetism. In effect, the spectroscopy we do today tells us about nuclear prop- erties and so combines atomic and nuclear physics. The main result of this experiment, the 4th of the semester, is to 1. measure the hyperfine splitting for each isotope, and compare with accepted values, with the fol- lowing details in mind: (a) what is the hyperfine splitting of the ground 2 state, S1=2 term? Do we need saturation- absorption techniques for this? (b) what are the hyperfine splittings of the ex- 2 cited state, P3=2 term, that can be reached with a nominal wavelength of 780nm from the ground state? Here we need saturation- absorption techniques to perform sub-Doppler FIG. 1. Note the four 'blobs'. Why are there four? Which spectroscopy, certainly. Help the reader un- 85 are associated with Rb37, and so on. If all goes swimm- derstand what is entailed in the technique, ingly, we'll get an absorption spectrum that looks much line both experimentally and theoretically. You the figure below the setup. The etalon data will be needed to will need to explain what `saturation' means. make the abscissa something proportional to frequency. The The saturation intensity is an important fig- accepted value of the gap between the 2 outermost dips is ure of merit. -
Scientific and Related Works of Chen Ning Yang
Scientific and Related Works of Chen Ning Yang [42a] C. N. Yang. Group Theory and the Vibration of Polyatomic Molecules. B.Sc. thesis, National Southwest Associated University (1942). [44a] C. N. Yang. On the Uniqueness of Young's Differentials. Bull. Amer. Math. Soc. 50, 373 (1944). [44b] C. N. Yang. Variation of Interaction Energy with Change of Lattice Constants and Change of Degree of Order. Chinese J. of Phys. 5, 138 (1944). [44c] C. N. Yang. Investigations in the Statistical Theory of Superlattices. M.Sc. thesis, National Tsing Hua University (1944). [45a] C. N. Yang. A Generalization of the Quasi-Chemical Method in the Statistical Theory of Superlattices. J. Chem. Phys. 13, 66 (1945). [45b] C. N. Yang. The Critical Temperature and Discontinuity of Specific Heat of a Superlattice. Chinese J. Phys. 6, 59 (1945). [46a] James Alexander, Geoffrey Chew, Walter Salove, Chen Yang. Translation of the 1933 Pauli article in Handbuch der Physik, volume 14, Part II; Chapter 2, Section B. [47a] C. N. Yang. On Quantized Space-Time. Phys. Rev. 72, 874 (1947). [47b] C. N. Yang and Y. Y. Li. General Theory of the Quasi-Chemical Method in the Statistical Theory of Superlattices. Chinese J. Phys. 7, 59 (1947). [48a] C. N. Yang. On the Angular Distribution in Nuclear Reactions and Coincidence Measurements. Phys. Rev. 74, 764 (1948). 2 [48b] S. K. Allison, H. V. Argo, W. R. Arnold, L. del Rosario, H. A. Wilcox and C. N. Yang. Measurement of Short Range Nuclear Recoils from Disintegrations of the Light Elements. Phys. Rev. 74, 1233 (1948). [48c] C. -
Dr. Abraham Pais Dr. Pais Was Born in Amsterdam on May 19, 1918. He
Director's Office: Faculty Files: Box 25: Pais, Abraham, Permanent Member From the Shelby White and Leon Levy Archives Center, Institute for Advanced Study, Princeton, NJ, USA Dr. Abraham Pais Dr. Pais was born i n Amsterdam on May 19, 1918. He obtained his Doctor's Degree at the University of Utrecht in 1941. During the years of the occupation, he continued to work under conditions of great difficulty, and the year after the war he was an assistant at the Insti- tute of Theoretical Physics in Copenhagen, In the fall of 1946, Dr. Pais came to the Institute for Advanced Study. ~he record of Dr. Pais' work in the last decade is almost a history of the efforts to clar ify our understanding of basic atomic theory and of the nature of elementary particles. Pais first proposed the compensa- tion theories of elenientary particles, and much of his work tas been devoted. to exploring the success and limitations of these theories, and indicating the radical character of the revisions which will be needed before they can successfully describe the sub-atomic world. Pais has made important contri- butions to nuclear theory and to electrodynamics . He is one of the few young theoretical physicists who within the last decade have enriched our understanding of physics. Statement prepared by J . R. Oppenheim.er Enclosure: Bibliography of papers by Dr. Pais Director's Office: Faculty Files: Box 25: Pais, Abraham, Permanent Member From the Shelby White and Leon Levy Archives Center, Institute for Advanced Study, Princeton, NJ, USA PUBLICATIONS OF ABRAHllJ~ PAIS The ener gy moment um tensor in projective r elativity theor y, Physi ca 8 (1941), 1137-116o . -
Julian Seymour Schwinger Papers, 1920-1994
http://oac.cdlib.org/findaid/ark:/13030/tf5870062x No online items Finding Aid for the Julian Seymour Schwinger Papers, 1920-1994 Processed by Russell Johnson and Charlotte B. Brown; machine-readable finding aid created by Caroline Cubé UCLA Library, Department of Special Collections Manuscripts Division Room A1713, Charles E. Young Research Library Box 951575 Los Angeles, CA 90095-1575 Email: [email protected] URL: http://www.library.ucla.edu/libraries/special/scweb/ © 1999 The Regents of the University of California. All rights reserved. Finding Aid for the Julian 371 1 Seymour Schwinger Papers, 1920-1994 Finding Aid for the Julian Seymour Schwinger Papers, 1920-1994 Collection number: 371 UCLA Library, Department of Special Collections Manuscripts Division Los Angeles, CA Contact Information Manuscripts Division UCLA Library, Department of Special Collections Room A1713, Charles E. Young Research Library Box 951575 Los Angeles, CA 90095-1575 Telephone: 310/825-4988 (10:00 a.m. - 4:45 p.m., Pacific Time) Email: [email protected] URL: http://www.library.ucla.edu/libraries/special/scweb/ Processed by: Charlotte B. Brown, 13 October 1995 and Russell A. Johnson, 12 February 1997 Encoded by: Caroline Cubé Online finding aid edited by: Josh Fiala, November 2002 © 1999 The Regents of the University of California. All rights reserved. Descriptive Summary Title: Julian Seymour Schwinger Papers, Date (inclusive): 1920-1994 Collection number: 371 Creator: Schwinger, Julian Seymour, 1918- Extent: 28 cartons (28 linear ft.) 1 oversize box Repository: University of California, Los Angeles. Library. Department of Special Collections. Los Angeles, California 90095-1575 Abstract: Julian Seymour Schwinger (1918-1994) worked with J. -
The Concept of the Photon—Revisited
The concept of the photon—revisited Ashok Muthukrishnan,1 Marlan O. Scully,1,2 and M. Suhail Zubairy1,3 1Institute for Quantum Studies and Department of Physics, Texas A&M University, College Station, TX 77843 2Departments of Chemistry and Aerospace and Mechanical Engineering, Princeton University, Princeton, NJ 08544 3Department of Electronics, Quaid-i-Azam University, Islamabad, Pakistan The photon concept is one of the most debated issues in the history of physical science. Some thirty years ago, we published an article in Physics Today entitled “The Concept of the Photon,”1 in which we described the “photon” as a classical electromagnetic field plus the fluctuations associated with the vacuum. However, subsequent developments required us to envision the photon as an intrinsically quantum mechanical entity, whose basic physics is much deeper than can be explained by the simple ‘classical wave plus vacuum fluctuations’ picture. These ideas and the extensions of our conceptual understanding are discussed in detail in our recent quantum optics book.2 In this article we revisit the photon concept based on examples from these sources and more. © 2003 Optical Society of America OCIS codes: 270.0270, 260.0260. he “photon” is a quintessentially twentieth-century con- on are vacuum fluctuations (as in our earlier article1), and as- Tcept, intimately tied to the birth of quantum mechanics pects of many-particle correlations (as in our recent book2). and quantum electrodynamics. However, the root of the idea Examples of the first are spontaneous emission, Lamb shift, may be said to be much older, as old as the historical debate and the scattering of atoms off the vacuum field at the en- on the nature of light itself – whether it is a wave or a particle trance to a micromaser. -
Joaquin M. Luttinger 1923–1997
Joaquin M. Luttinger 1923–1997 A Biographical Memoir by Walter Kohn ©2014 National Academy of Sciences. Any opinions expressed in this memoir are those of the author and do not necessarily reflect the views of the National Academy of Sciences. JOAQUIN MAZDAK LUTTINGER December 2, 1923–April 6, 1997 Elected to the NAS, 1976 The brilliant mathematical and theoretical physicist Joaquin M. Luttinger died at the age of 73 years in the city of his birth, New York, which he deeply loved throughout his life. He had been in good spirits a few days earlier when he said to Walter Kohn (WK), his longtime collaborator and friend, that he was dying a happy man thanks to the loving care during his last illness by his former wife, Abigail Thomas, and by his stepdaughter, Jennifer Waddell. Luttinger’s work was marked by his exceptional ability to illuminate physical properties and phenomena through Visual Archives. Emilio Segrè Photograph courtesy the use of appropriate and beautiful mathematics. His writings and lectures were widely appreciated for their clarity and fine literary quality. With Luttinger’s death, an By Walter Kohn influential voice that helped shape the scientific discourse of his time, especially in condensed-matter physics, was stilled, but many of his ideas live on. For example, his famous 1963 paper on condensed one-dimensional fermion systems, now known as Tomonaga-Luttinger liquids,1, 2 or simply Luttinger liquids, continues to have a strong influence on research on 1-D electronic dynamics. In the 1950s and ’60s, Luttinger also was one of the great figures who helped construct the present canon of classic many-body theory while at the same time laying founda- tions for present-day revisions.