Decoherence and the Transition from Quantum to Classical—Revisited
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Arxiv:Quant-Ph/0105127V3 19 Jun 2003
DECOHERENCE, EINSELECTION, AND THE QUANTUM ORIGINS OF THE CLASSICAL Wojciech Hubert Zurek Theory Division, LANL, Mail Stop B288 Los Alamos, New Mexico 87545 Decoherence is caused by the interaction with the en- A. The problem: Hilbert space is big 2 vironment which in effect monitors certain observables 1. Copenhagen Interpretation 2 of the system, destroying coherence between the pointer 2. Many Worlds Interpretation 3 B. Decoherence and einselection 3 states corresponding to their eigenvalues. This leads C. The nature of the resolution and the role of envariance4 to environment-induced superselection or einselection, a quantum process associated with selective loss of infor- D. Existential Interpretation and ‘Quantum Darwinism’4 mation. Einselected pointer states are stable. They can retain correlations with the rest of the Universe in spite II. QUANTUM MEASUREMENTS 5 of the environment. Einselection enforces classicality by A. Quantum conditional dynamics 5 imposing an effective ban on the vast majority of the 1. Controlled not and a bit-by-bit measurement 6 Hilbert space, eliminating especially the flagrantly non- 2. Measurements and controlled shifts. 7 local “Schr¨odinger cat” states. Classical structure of 3. Amplification 7 B. Information transfer in measurements 9 phase space emerges from the quantum Hilbert space in 1. Action per bit 9 the appropriate macroscopic limit: Combination of einse- C. “Collapse” analogue in a classical measurement 9 lection with dynamics leads to the idealizations of a point and of a classical trajectory. In measurements, einselec- III. CHAOS AND LOSS OF CORRESPONDENCE 11 tion replaces quantum entanglement between the appa- A. Loss of the quantum-classical correspondence 11 B. -
A New Sletter from the Ins T Itute F OR Qu Antum C O Mput Ing , U N Ive R S
dition E pecial S | Bit Issue 20 Issue New A NEWSLETTER FROM THE INSTITUTE FOR QUANTUM COMPUTING, UNIVERSITY OF WATERLOO, WaTERLOO, ONTARIO, CANADA | C I S | NE CANADA NSTITUTE FOR QUANTUM QUANTUM FOR NSTITUTE PECIAL OMPUTING | NE NEWBIT ThisE is a state-of-the-art “ DITION | | research facility where I SSUE 20 SSUE scientistsW and students from many disciplinesBIT | will work Photos by Jonathan Bielaski W together toward the next BIT | I NSTITUTE FOR QUANTUM QUANTUM FOR NSTITUTE big breakthroughsI in science SSUE 20 | SSUE | and technology. SPECIAL EDITION I ” uantum Valley SSUE 20 | SSUE FERIDUN HAMDULLAHPUR, C OMPUTING, President, University of Waterloo Takes the Stage S S The science of the incredibly small has taken a giant leap at the Just asPECIAL the discoveries and PECIAL “ University of Waterloo. On Friday, Sept. 21 the MIKE & OPHELIA innovations at the Bell Labs LAZARIDIS QUANTUM-NANO CENTRE officially opened with a U led to the companies that ceremony attended by more than 1,200 guests and dignitaries, | NIVERSITY OF WATERLOO, ONTARIO, CANADA | NE CANADA ONTARIO, NIVERSITY OF WATERLOO, created SiliconI Valley, so will, including Prof. STEPHEN HAWKING. NSTITUTE F NSTITUTE E E I predict,DITION | the discoveries and DITION | innovationsC of the Quantum- OMPUTING, Nano Centre lead to the creation of companies that will lead to Distinguished I NSTITUTE FOR QUANTUM QUANTUM FOR NSTITUTE guests at the I Waterloo Region becoming NSTITUTE FOR QUANTUM QUANTUM FOR NSTITUTE O ribbon cutting of known as R QUANTUM the Quantum Valley. ” the Quantum-Nano Centre included Prof. U MIKE LAZARIDIS, STEPHEN HAWKING, NIVERSITY OF WATERLOO, ONTARIO, CANADA | NE CANADA ONTARIO, NIVERSITY OF WATERLOO, MPP JOHN MILLOY, Entrepreneur and philanthropist and MP PETER BRAID (behind). -
Annual Report to Industry Canada Covering The
Annual Report to Industry Canada Covering the Objectives, Activities and Finances for the period August 1, 2008 to July 31, 2009 and Statement of Objectives for Next Year and the Future Perimeter Institute for Theoretical Physics 31 Caroline Street North Waterloo, Ontario N2L 2Y5 Table of Contents Pages Period A. August 1, 2008 to July 31, 2009 Objectives, Activities and Finances 2-52 Statement of Objectives, Introduction Objectives 1-12 with Related Activities and Achievements Financial Statements, Expenditures, Criteria and Investment Strategy Period B. August 1, 2009 and Beyond Statement of Objectives for Next Year and Future 53-54 1 Statement of Objectives Introduction In 2008-9, the Institute achieved many important objectives of its mandate, which is to advance pure research in specific areas of theoretical physics, and to provide high quality outreach programs that educate and inspire the Canadian public, particularly young people, about the importance of basic research, discovery and innovation. Full details are provided in the body of the report below, but it is worth highlighting several major milestones. These include: In October 2008, Prof. Neil Turok officially became Director of Perimeter Institute. Dr. Turok brings outstanding credentials both as a scientist and as a visionary leader, with the ability and ambition to position PI among the best theoretical physics research institutes in the world. Throughout the last year, Perimeter Institute‘s growing reputation and targeted recruitment activities led to an increased number of scientific visitors, and rapid growth of its research community. Chart 1. Growth of PI scientific staff and associated researchers since inception, 2001-2009. -
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. -
Ion Trap Nobel
The Nobel Prize in Physics 2012 Serge Haroche, David J. Wineland The Nobel Prize in Physics 2012 was awarded jointly to Serge Haroche and David J. Wineland "for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems" David J. Wineland, U.S. citizen. Born 1944 in Milwaukee, WI, USA. Ph.D. 1970 Serge Haroche, French citizen. Born 1944 in Casablanca, Morocco. Ph.D. from Harvard University, Cambridge, MA, USA. Group Leader and NIST Fellow at 1971 from Université Pierre et Marie Curie, Paris, France. Professor at National Institute of Standards and Technology (NIST) and University of Colorado Collège de France and Ecole Normale Supérieure, Paris, France. Boulder, CO, USA www.college-de-france.fr/site/en-serge-haroche/biography.htm www.nist.gov/pml/div688/grp10/index.cfm A laser is used to suppress the ion’s thermal motion in the trap, and to electrode control and measure the trapped ion. lasers ions Electrodes keep the beryllium ions inside a trap. electrode electrode Figure 2. In David Wineland’s laboratory in Boulder, Colorado, electrically charged atoms or ions are kept inside a trap by surrounding electric fields. One of the secrets behind Wineland’s breakthrough is mastery of the art of using laser beams and creating laser pulses. A laser is used to put the ion in its lowest energy state and thus enabling the study of quantum phenomena with the trapped ion. Controlling single photons in a trap Serge Haroche and his research group employ a diferent method to reveal the mysteries of the quantum world. -
Einselection Without Pointer States
Einselection without pointer states Einselection without pointer states - Decoherence under weak interaction Christian Gogolin Universit¨atW¨urzburg 2009-12-16 C. Gogolin j Universit¨atW¨urzburg j 2009-12-16 1 / 26 Einselection without pointer states j Introduction New foundation for Statistical Mechanics X Thermodynamics X Statistical Mechanics Second Law ergodicity equal a priory probabilities Classical Mechanics [2, 3] C. Gogolin j Universit¨atW¨urzburg j 2009-12-16 2 / 26 Einselection without pointer states j Introduction New foundation for Statistical Mechanics X Thermodynamics X Statistical Mechanics Second Law ergodicity ? equal a priory probabilities Classical Mechanics ? [2, 3] C. Gogolin j Universit¨atW¨urzburg j 2009-12-16 2 / 26 Einselection without pointer states j Introduction New foundation for Statistical Mechanics X Thermodynamics X Statistical Mechanics [2, 3] C. Gogolin j Universit¨atW¨urzburg j 2009-12-16 2 / 26 Einselection without pointer states j Introduction New foundation for Statistical Mechanics X Thermodynamics X Statistical Mechanics * Quantum Mechanics X [2, 3] C. Gogolin j Universit¨atW¨urzburg j 2009-12-16 2 / 26 quantum mechanical orbitals discrete energy levels coherent superpositions hopping Einselection without pointer states j Introduction Why do electrons hop between energy eigenstates? C. Gogolin j Universit¨atW¨urzburg j 2009-12-16 3 / 26 discrete energy levels hopping Einselection without pointer states j Introduction Why do electrons hop between energy eigenstates? quantum mechanical orbitals coherent superpositions C. Gogolin j Universit¨atW¨urzburg j 2009-12-16 3 / 26 Einselection without pointer states j Introduction Why do electrons hop between energy eigenstates? quantum mechanical orbitals discrete energy levels coherent superpositions hopping C. -
Nobel 2012: Trapped Ions and Photons
FEATURES Nobel 2012: Trapped ions and photons l Michel Brune1, Jean-Michel Raimond1, Claude Cohen-Tannoudji 1,2 - DOI: 10.1051/epn/2012601 l 1 Laboratoire Kastler Brossel, ENS, CNRS, UMPC Paris 6, 24 rue Lhomond, 75005 Paris, France l 2 Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France m This colorized The 2012 Nobel prize in physics has been awarded jointly to Serge Haroche image shows the fluorescence from three (Collège de France and Ecole Normale Supérieure) and David Wineland (National trapped beryllium ions illuminated with Institute for Standards and Technology, USA) “for ground-breaking experimental an ultraviolet laser methods that enable measuring and manipulation of individual quantum systems”. beam. Black and blue areas indicate lower intensity, and red and white higher intensity. hat are these methods, why are they For instance, Einstein and Bohr once imagined weighing NIST physicists used jointly recognized? a photon trapped forever in a box, covered by perfect three beryllium ions to demonstrate a crucial The key endeavour in the last century mirrors. These gedankenexperiments and their “ridicu- step in a procedure that of quantum physics has been the explo- lous consequences”, as Schrödinger once stated, played could enable future ration of the coupling between matter and electromag- a considerable role in the genesis of quantum physics quantum computers W to break today's netic radiation. For a long time, the available experimental interpretation. The technical progress made these most commonly used techniques were limited to a large number of atoms and experiments possible. One can now realize some of the encryption codes. -
A Model-Theoretic Interpretation of Environmentally-Induced
A model-theoretic interpretation of environmentally-induced superselection Chris Fields 815 East Palace # 14 Santa Fe, NM 87501 USA fi[email protected] November 28, 2018 Abstract The question of what constitutes a “system” is foundational to quantum mea- surement theory. Environmentally-induced superselection or “einselection” has been proposed as an observer-independent mechanism by which apparently classical sys- tems “emerge” from physical interactions between degrees of freedom described com- pletely quantum-mechanically. It is shown here that einselection can only generate classical systems if the “environment” is assumed a priori to be classical; einselection therefore does not provide an observer-independent mechanism by which classicality can emerge from quantum dynamics. Einselection is then reformulated in terms of positive operator-valued measures (POVMs) acting on a global quantum state. It is shown that this re-formulation enables a natural interpretation of apparently-classical systems as virtual machines that requires no assumptions beyond those of classical arXiv:1202.1019v2 [quant-ph] 13 May 2012 computer science. Keywords: Decoherence, Einselection, POVMs, Emergence, Observer, Quantum-to-classical transition 1 Introduction The concept of environmentally-induced superselection or “einselection” was introduced into quantum mechanics by W. Zurek [1, 2] as a solution to the “preferred-basis problem,” 1 the problem of selecting one from among the arbitrarily many possible sets of basis vectors spanning the Hilbert space of a system of interest. Zurek’s solution was brilliantly simple: it transferred the preferred basis problem from the observer to the environment in which the system of interest is embedded, and then solved the problem relative to the environment. -
Decoherence, Einselection, and the Quantum Origins of the Classical
REVIEWS OF MODERN PHYSICS, VOLUME 75, JULY 2003 Decoherence, einselection, and the quantum origins of the classical Wojciech Hubert Zurek Theory Division, LANL, Mail Stop B210, Los Alamos, New Mexico 87545 (Published 22 May 2003) The manner in which states of some quantum systems become effectively classical is of great significance for the foundations of quantum physics, as well as for problems of practical interest such as quantum engineering. In the past two decades it has become increasingly clear that many (perhaps all) of the symptoms of classicality can be induced in quantum systems by their environments. Thus decoherence is caused by the interaction in which the environment in effect monitors certain observables of the system, destroying coherence between the pointer states corresponding to their eigenvalues. This leads to environment-induced superselection or einselection, a quantum process associated with selective loss of information. Einselected pointer states are stable. They can retain correlations with the rest of the universe in spite of the environment. Einselection enforces classicality by imposing an effective ban on the vast majority of the Hilbert space, eliminating especially the flagrantly nonlocal ‘‘Schro¨ dinger-cat states.’’ The classical structure of phase space emerges from the quantum Hilbert space in the appropriate macroscopic limit. Combination of einselection with dynamics leads to the idealizations of a point and of a classical trajectory. In measurements, einselection replaces quantum entanglement between -
EUGENE PAUL WIGNER November 17, 1902–January 1, 1995
NATIONAL ACADEMY OF SCIENCES E U G ENE PAUL WI G NER 1902—1995 A Biographical Memoir by FR E D E R I C K S E I T Z , E RICH V OG T , A N D AL V I N M. W E I NBER G Any opinions expressed in this memoir are those of the author(s) and do not necessarily reflect the views of the National Academy of Sciences. Biographical Memoir COPYRIGHT 1998 NATIONAL ACADEMIES PRESS WASHINGTON D.C. Courtesy of Atoms for Peace Awards, Inc. EUGENE PAUL WIGNER November 17, 1902–January 1, 1995 BY FREDERICK SEITZ, ERICH VOGT, AND ALVIN M. WEINBERG UGENE WIGNER WAS A towering leader of modern physics Efor more than half of the twentieth century. While his greatest renown was associated with the introduction of sym- metry theory to quantum physics and chemistry, for which he was awarded the Nobel Prize in physics for 1963, his scientific work encompassed an astonishing breadth of sci- ence, perhaps unparalleled during his time. In preparing this memoir, we have the impression we are attempting to record the monumental achievements of half a dozen scientists. There is the Wigner who demonstrated that symmetry principles are of great importance in quan- tum mechanics; who pioneered the application of quantum mechanics in the fields of chemical kinetics and the theory of solids; who was the first nuclear engineer; who formu- lated many of the most basic ideas in nuclear physics and nuclear chemistry; who was the prophet of quantum chaos; who served as a mathematician and philosopher of science; and the Wigner who was the supervisor and mentor of more than forty Ph.D. -
El Premio Nobel De Fısica De 2012
El premio Nobel de f´ısica de 2012 Jose´ Mar´ıa Filardo Bassalo* Abstract Palabras clave: Premio nobel de f´ısica de 2012; Haroche y In this article we will talk about the 2012 Nobel Prize in Phy- Wineland, manipulacion´ cuantica.´ sics, awarded to the physicists, the frenchman Serge Haroche and the north-american David Geffrey Wineland for ground- Serge Haroche breaking experimental methods that enable measuring and ma- El premio nobel de f´ısica (PNF) de 2012 fue con- nipulation of individual quantum systems. cedido a los f´ısicos, el frances´ Serge Haroche (n. 1944) y el norteamericano David Geffrey Wine- Keywords: 2012 Physics Nobel Prize; Haroche and Wineland; Quantum Manipulation. land (n. 1944) por el desarrollo de tecnicas´ experimen- tales capaces de medir y manipular sistemas qu´ımi- Resumen cos individuales por medio de la optica´ cuanti-´ En este art´ıculo trataremos del premio nobel de f´ısica de 2012 ca. Con todo, emplearon tecnicas´ distintas y comple- concedido a los f´ısicos, el frances´ Serge Haroche y al norteame- mentarias: Haroche utilizo´ fotones de atomos´ carga- ricano David Geffrey Wineland por el desarrollo de tecnicas´ ex- dos (iones) entrampados; Wineland entrampo´ los io- perimentales capaces de medir y manipular sistemas cuanticos´ nes y empleo´ fotones para modificar su estado individuales. cuantico.´ *http://www.amazon.com.br Recibido: 16 de abril de 2013. Comencemos viendo algo de la vida y del trabajo de es- Aceptado: 09 de octubre de 2013. tos premiados, as´ı como la colaboracion´ en estos temas 5 6 ContactoS 92, 5–10 (2014) por algunas f´ısicos brasilenos,˜ por ejemplo Nicim Za- gury (n. -
Adobe Acrobat PDF Document
BIOGRAPHICAL SKETCH of HUGH EVERETT, III. Eugene Shikhovtsev ul. Dzerjinskogo 11-16, Kostroma, 156005, Russia [email protected] ©2003 Eugene B. Shikhovtsev and Kenneth W. Ford. All rights reserved. Sources used for this biographical sketch include papers of Hugh Everett, III stored in the Niels Bohr Library of the American Institute of Physics; Graduate Alumni Files in Seeley G. Mudd Manuscript Library, Princeton University; personal correspondence of the author; and information found on the Internet. The author is deeply indebted to Kenneth Ford for great assistance in polishing (often rewriting!) the English and for valuable editorial remarks and additions. If you want to get an interesting perspective do not think of Hugh as a traditional 20th century physicist but more of a Renaissance man with interests and skills in many different areas. He was smart and lots of things interested him and he brought the same general conceptual methodology to solve them. The subject matter was not so important as the solution ideas. Donald Reisler [1] Someone once noted that Hugh Everett should have been declared a “national resource,” and given all the time and resources he needed to develop new theories. Joseph George Caldwell [1a] This material may be freely used for personal or educational purposes provided acknowledgement is given to Eugene B. Shikhovtsev, author ([email protected]), and Kenneth W. Ford, editor ([email protected]). To request permission for other uses, contact the author or editor. CONTENTS 1 Family and Childhood Einstein letter (1943) Catholic University of America in Washington (1950-1953). Chemical engineering. Princeton University (1953-1956).