Bohr's Way to Defining Complementarity(*)
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Unit 1 Old Quantum Theory
UNIT 1 OLD QUANTUM THEORY Structure Introduction Objectives li;,:overy of Sub-atomic Particles Earlier Atom Models Light as clectromagnetic Wave Failures of Classical Physics Black Body Radiation '1 Heat Capacity Variation Photoelectric Effect Atomic Spectra Planck's Quantum Theory, Black Body ~diation. and Heat Capacity Variation Einstein's Theory of Photoelectric Effect Bohr Atom Model Calculation of Radius of Orbits Energy of an Electron in an Orbit Atomic Spectra and Bohr's Theory Critical Analysis of Bohr's Theory Refinements in the Atomic Spectra The61-y Summary Terminal Questions Answers 1.1 INTRODUCTION The ideas of classical mechanics developed by Galileo, Kepler and Newton, when applied to atomic and molecular systems were found to be inadequate. Need was felt for a theory to describe, correlate and predict the behaviour of the sub-atomic particles. The quantum theory, proposed by Max Planck and applied by Einstein and Bohr to explain different aspects of behaviour of matter, is an important milestone in the formulation of the modern concept of atom. In this unit, we will study how black body radiation, heat capacity variation, photoelectric effect and atomic spectra of hydrogen can be explained on the basis of theories proposed by Max Planck, Einstein and Bohr. They based their theories on the postulate that all interactions between matter and radiation occur in terms of definite packets of energy, known as quanta. Their ideas, when extended further, led to the evolution of wave mechanics, which shows the dual nature of matter -
Marie Curie and Her Time
Marie Curie and Her Time by Hélène Langevin-Joliot to pass our lives near each other hypnotized by our dreams, your patriotic dream, our humanitarian dream, arie Curie (1867–1934) belongs to that exclu- and our scientific dream.” sive group of women whose worldwide rec- Frederick Soddy wrote about Marie that she was Mognition and fame have endured for a century “the most beautiful discovery of Pierre Curie.” Of or more. She was indeed one of the major agents of course, it might also be said that Pierre Curie was the scientific revolution which allowed experimen- “the most beautiful discovery of Marie Skłodowska.” tal investigation to extend beyond the macroscopic It is difficult to imagine more contrasting personali- world. Her work placed the first stone in the founda- ties than those of Pierre and of Marie. In spite of that, tion of a new discipline: radiochemistry. And Curie’s or because of that, they complemented each other achievements are even more remarkable since they astonishingly well. Pierre was as dreamy as Marie was occurred in the field of science, an intellectual activ- organized. At the same time, they shared similar ideas ity traditionally forbidden to women. However, these about family and society. accomplishments alone don’t seem to fully explain the near mythic status of Marie Curie today. One hundred years ago, she was often considered to be just an assistant to her husband. Perhaps the reason her name still resonates is because of the compelling story of her life and her intriguing personality. The Most Beautiful Discovery of Pierre Curie The story of the young Maria Skłodowska leaving In this iconic photograph of participants at the Fifth her native Poland to pursue upper-level studies in Solvay Conference in 1927, Marie Curie is third from Paris sounds like something out of a novel. -
Quantum Theory at the Crossroads : Reconsidering the 1927 Solvay
QUANTUM THEORY AT THE CROSSROADS Reconsidering the 1927 Solvay Conference GUIDO BACCIAGALUPPI ANTONY VALENTINI 8 CAMBRIDGE ::: UNIVERSITY PRESS Contents List of illustrations page xii Preface xv Abbreviations xxi Typographic conventions xxiii Note on the bibliography and the index xxiii Permissions and copyright notices xxiii Part I Perspectives on the 1927 Solvay conference 1 Historical introduction 3 1.1 Ernest Solvay and the Institute of Physics 3 1.2 War and international relations 6 1.3 Scientific planning and background 8 1.4 Further details of planning 15 1.5 The Solvay meeting 18 1.6 The editing of the proceedings 20 1. 7 Conclusion 21 Archival notes 23 2 De Broglie's pilot-wave theory 27 2.1 Background 27 2.2 A new approach to particle dynamics: 1923-1924 33 2.2.1 First papers on pilot-wave theory (1923) 34 2.2.2 Thesis (1924) 39 2.2.3 Optical interference fringes: November 1924 49 2.3 Towards a complete pilot-wave dynamics: 1925-1927 51 2.3.1 'Structure': Journal de Physique, May 1927 55 2.3.2 Significance of de Broglie's 'Structure' paper 65 vii viii Contents 2.4 1927 Solvay report: the new dynamics of quanta 67 2.5 Significance of de Broglie's work from 1923 to 1927 76 Archival notes 79 3 From matrix mechanics to quantum mechanics 80 3.1 Summary of Born and Heisenberg's report 81 3.2 Writing of the report 84 3.3 Formalism 85 3.3.1 Before matrix mechanics 85 3.3.2 Matrix mechanics 86 3.3.3 Formal extensions of matrix mechanics 90 3.4 Interpretation 92 3.4.1 Matrix mechanics, Born and Wiener 93 3.4.2 Born and Jordan on guiding -
Beyond the Quantum
Beyond the Quantum Antony Valentini Theoretical Physics Group, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom. email: [email protected] At the 1927 Solvay conference, three different theories of quantum mechanics were presented; however, the physicists present failed to reach a consensus. To- day, many fundamental questions about quantum physics remain unanswered. One of the theories presented at the conference was Louis de Broglie's pilot- wave dynamics. This work was subsequently neglected in historical accounts; however, recent studies of de Broglie's original idea have rediscovered a power- ful and original theory. In de Broglie's theory, quantum theory emerges as a special subset of a wider physics, which allows non-local signals and violation of the uncertainty principle. Experimental evidence for this new physics might be found in the cosmological-microwave-background anisotropies and with the detection of relic particles with exotic new properties predicted by the theory. 1 Introduction 2 A tower of Babel 3 Pilot-wave dynamics 4 The renaissance of de Broglie's theory 5 What if pilot-wave theory is right? 6 The new physics of quantum non-equilibrium 7 The quantum conspiracy Published in: Physics World, November 2009, pp. 32{37. arXiv:1001.2758v1 [quant-ph] 15 Jan 2010 1 1 Introduction After some 80 years, the meaning of quantum theory remains as controversial as ever. The theory, as presented in textbooks, involves a human observer performing experiments with microscopic quantum systems using macroscopic classical apparatus. The quantum system is described by a wavefunction { a mathematical object that is used to calculate probabilities but which gives no clear description of the state of reality of a single system. -
The Age of Chance Reserved for the Winning Side of the Struggle
BOOKS & ARTS NATURE|Vol 446|22 March 2007 unfortunately, that Lindley’s perceptive and sympathetic treatment of ideas and figures is The age of chance reserved for the winning side of the struggle. He marginalizes Einstein’s concerns by pre- Uncertainty: Einstein, Heisenberg, Bohr, posal for a radically non-newtonian dynamic senting him as a young revolutionary turned and the Struggle for the Soul of Science theory in which particles followed trajectories old reactionary. Lindley keeps returning to by David Lindley determined by an associated wave. De Bro- Einstein’s desire for causality, while down- Doubleday: 2007. 272 pp. $26 glie showed how this could account for basic playing Einstein’s equally strong insistence that interference phenomena (as waves) as well as physics, causal or not, should deal with nature Arthur Fine quantized energy (as particles). That drew it to itself, not just our observations. The author In Uncertainty, David Lindley tells the intrigu- the attention of Einstein and Schrödinger, who also overlooks Einstein’s radical critique of the ing tale of how Albert Einstein, Werner found the ideas promising, and to Heisenberg, classical, physical concepts used in quantum Heisenberg and Niels Bohr (among others) Pauli and Bohr, who felt threatened by them. theory, as well as his programme for develop- struggled to create and understand the new But de Broglie lacked a general treatment of ing new concepts, and his eventual openness quantum physics. Lindley organizes his tale the waves that guided his particles, and that is to an algebraic, rather than a spatiotemporal, around the issue of indeterminism, which Max where wave mechanics comes in. -
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. -
Theory and Experiment in the Quantum-Relativity Revolution
Theory and Experiment in the Quantum-Relativity Revolution expanded version of lecture presented at American Physical Society meeting, 2/14/10 (Abraham Pais History of Physics Prize for 2009) by Stephen G. Brush* Abstract Does new scientific knowledge come from theory (whose predictions are confirmed by experiment) or from experiment (whose results are explained by theory)? Either can happen, depending on whether theory is ahead of experiment or experiment is ahead of theory at a particular time. In the first case, new theoretical hypotheses are made and their predictions are tested by experiments. But even when the predictions are successful, we can’t be sure that some other hypothesis might not have produced the same prediction. In the second case, as in a detective story, there are already enough facts, but several theories have failed to explain them. When a new hypothesis plausibly explains all of the facts, it may be quickly accepted before any further experiments are done. In the quantum-relativity revolution there are examples of both situations. Because of the two-stage development of both relativity (“special,” then “general”) and quantum theory (“old,” then “quantum mechanics”) in the period 1905-1930, we can make a double comparison of acceptance by prediction and by explanation. A curious anti- symmetry is revealed and discussed. _____________ *Distinguished University Professor (Emeritus) of the History of Science, University of Maryland. Home address: 108 Meadowlark Terrace, Glen Mills, PA 19342. Comments welcome. 1 “Science walks forward on two feet, namely theory and experiment. ... Sometimes it is only one foot which is put forward first, sometimes the other, but continuous progress is only made by the use of both – by theorizing and then testing, or by finding new relations in the process of experimenting and then bringing the theoretical foot up and pushing it on beyond, and so on in unending alterations.” Robert A. -
FROM NIELS BOHR to QUANTUM COMPUTING* Klaus Mølmer, Department of Physics and Astronomy, University of Aarhus, Denmark†
FRYBA1 Proceedings of IPAC2017, Copenhagen, Denmark FROM NIELS BOHR TO QUANTUM COMPUTING* Klaus Mølmer, Department of Physics and Astronomy, University of Aarhus, Denmark† Abstract quickly appreciated that cooling of atoms, squeezing of Quantum mechanics replaces determinism with proba- light, control of molecular wave packets … would enable bilistic predictions for measurement outcomes and de- new precise studies and applications, but also truly revo- scribes microscopic particles by wave functions as if they lutionary possibilities emerged. are simultaneously at different locations. The paradoxical Among them were ideas to employ quantum mecha- properties of quantum mechanics caused painstaking nisms for applications outside of physics: quantum money discussions between Schrödinger, Einstein and Bohr who that cannot be counterfeited, unbreakable quantum cryp- disagreed fundamentally about the meaning of the theory. tograhy, and quantum computing. Richard Feynman’s Today, scientists and engineers try to harness the hotly 1982 proposal for quantum computing also included the debated issues of those discussions for technological idea to simulate quantum many-body physics and chemis- applications in quantum encrypted data transmission and try by use of a suitably controllable quantum system. in quantum computing that uses quantum states to do Research in quantum computing has received much at- many calculations in parallel. tention since the theoretical proposal of promising algo- rithms in the mid 1990’s. Following generous funding INTRODUCTION for more than a decade, the European Union has just released its plan to sponsor a 1 Bn € Flagship in Quantum In 1913, Niels Bohr introduced his model of the atom Technologies, engaging both Industry and Academia. with an electron orbiting the atomic nucleus as a satellite Similar activities are operated at national level, and big in orbit around a planet. -
Introduction to Quantum Mechanics the Manchester Physics Series Generaleditors D
Introduction to Quantum Mechanics The Manchester Physics Series GeneralEditors D. J. SANDIFORD: F. MANDL: A. C. PHILLIPS Department of Physics and Astronomy, University of Manchester Properties of Matter: B. H. Flowers and E. Mendoza Statistical Physics: F. Mandl Second Edition Electromagnetism: I. S. Grant and W. R. Phillips Second Edition Statistics: R. J. Barlow Solid State Physics: J. R. Hook and H. E. Hall Second Edition Quantum Mechanics: F. Mandl Particle Physics: B. R. Martin and G. Shaw Second Edition The Physics of Stars: A. C. Phillips Second Edition Computing for Scientists: R. J. Barlow and A. R. Barnett Nuclear Physics: J. S. Lilley Introduction to Quantum Mechanics: A. C. Phillips INTRODUCTION TO QUANTUM MECHANICS A. C. Phillips Department of Physics andAstronomy University of Manchester Copyright # 2003 by John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, England National 01243 779777 International (44) 1243 779777 e-mail (for orders and customer service enquiries): [email protected] Visit our Home Page on http://www.wiley.co.uk or http://www.wiley.com 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, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency, 90 Tottenham Court Road, London, UK W1P 9HE, without the permission in writing -
Arxiv:Quant-Ph/0510180V1 24 Oct 2005 Einstein and the Quantum
TIFR/TH/05-39 27.9.2005 Einstein and the Quantum Virendra Singh Tata Institute of Fundamental Research Homi Bhabha Road, Mumbai 400 005, India Abstract We review here the main contributions of Einstein to the quantum theory. To put them in perspective we first give an account of Physics as it was before him. It is followed by a brief account of the problem of black body radiation which provided the context for Planck to introduce the idea of quantum. Einstein’s revolutionary paper of 1905 on light-quantum hypothesis is then described as well as an application of this idea to the photoelectric effect. We next take up a discussion of Einstein’s other contributions to old quantum theory. These include (i) his theory of specific heat of solids, which was the first application of quantum theory to matter, (ii) his discovery of wave-particle duality for light and (iii) Einstein’s A and B coefficients relating to the probabilities of emission and absorption of light by atomic systems and his discovery of radiation stimulated emission of light which provides the basis for laser action. We then describe Einstein’s contribution to quantum statistics viz Bose- Einstein Statistics and his prediction of Bose-Einstein condensation of a boson gas. Einstein played a pivotal role in the discovery of Quantum mechanics and this is briefly mentioned. After 1925 Einstein’s contributed mainly to the foundations of Quantum Mechanics. We arXiv:quant-ph/0510180v1 24 Oct 2005 choose to discuss here (i) his Ensemble (or Statistical) Interpretation of Quantum Mechanics and (ii) the discovery of Einstein-Podolsky-Rosen (EPR) correlations and the EPR theorem on the conflict between Einstein-Locality and the completeness of the formalism of Quantum Mechanics. -
Solvay Conference - Wikipedia, the Free Encyclopedia Page 1
Solvay Conference - Wikipedia, the free encyclopedia Page 1 Solvay Conference From Wikipedia, the free encyclopedia The International Solvay Institutes for Physics and Chemistry, located in Brussels, were founded by the Belgian industrialist Ernest Solvay in 1912, following the historic invitation-only 1911 Conseil Solvay , considered a turning point in the world of physics. The Institutes coordinate conferences, workshops, seminars, and colloquia.[1] Following the initial success of 1911, the Solvay Conferences (Conseils Solvay ) have been devoted to outstanding preeminent open problems in both physics and chemistry. The usual schedule is every three years, but there have been larger gaps. Photograph of the first conference in 1911 Contents at the Hotel Metropole. Seated (L-R): W. Nernst, M. Brillouin, E. Solvay, H. 1 Notable Solvay Conferences Lorentz, E. Warburg, J. Perrin, W. Wien, 1.1 First Conference M. Skłodowska-Curie, and H. Poincaré. 1.2 Third Conference Standing (L-R): R. Goldschmidt, M. 1.3 Fifth Conference Planck, H. Rubens, A. Sommerfeld, F. 2 Solvay Conferences on Physics Lindemann, M. de Broglie, M. Knudsen, 2.1 Conferences on Physics gallery F. Hasenöhrl, G. Hostelet, E. Herzen, J.H. 3 Solvay Conferences on Chemistry 3.1 Conferences on Chemistry Jeans, E. Rutherford, H. Kamerlingh gallery Onnes, A. Einstein and P. Langevin. 4 References 5 Further reading 6 External links Notable Solvay Conferences First Conference Hendrik A. Lorentz was chairman of the first Solvay Conference held in Brussels in the autumn of 1911. The subject was Radiation and the Quanta . This conference looked at the problems of having two approaches, namely the classical physics and quantum theory. -
The Renormalization of Charge and Temporality in Quantum Electrodynamics
The renormalization of charge and temporality in quantum electrodynamics Mario Bacelar Valente abstract In this article it is intended a closer look at the renormalization procedure used in quantum electrodynamics to cope with the divergent integrals that appear in higher-order calculations within the theory. The main focus will be the charge renormalization that reveals, in a clearer way than the mass renormalization, structural limitations present in quantum electrodynamics that are even more aggravating than the ones usually pointed at when considering the renormalization procedure. In this way we see that the possibility of charge renormalization is due to limitations of the theory in the temporal description of the interactions. 1 Introduction The appearance of divergent integrals in higher-order calculations in quantum electrodynamics where the so-called radiative corrections are taken into account has been seen as, at least, indicating that the theory fails for high energies. As J. Schwinger stated, “electrodynamics unquestionably requires revision at ultra-relativistic energies” (Aramaki 1989, 93). Even considering the accuracy of the theory at lower energies, Schwinger considered that the renormalization procedure, that permits avoiding the infinites in the results of the calculations, ultimately has to be excluded from physics (Cao 1993, 50). Regarding this problem the position of P. Dirac was even less sympathetic: “I am very dissatisfied with the situation, because this so-called “good theory” does involve neglecting infinities which appear in its equations” (Kragh 1990, 184). In general the position of leading physicists was very critical regarding quantum electrodynamics, and some pinpointed to structural problems that go beyond the high energy behaviour of quantum electrodynamics.