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Lecture Notes in Physics
Lecture Notes in Physics Editorial Board R. Beig, Wien, Austria J. Ehlers, Potsdam, Germany U. Frisch, Nice, France K. Hepp, Zurich,¨ Switzerland W. Hillebrandt, Garching, Germany D. Imboden, Zurich,¨ Switzerland R. L. Jaffe, Cambridge, MA, USA R. Kippenhahn, Gottingen,¨ Germany R. Lipowsky, Golm, Germany H. v. Lohneysen,¨ Karlsruhe, Germany I. Ojima, Kyoto, Japan H. A. Weidenmuller,¨ Heidelberg, Germany J. Wess, Munchen,¨ Germany J. Zittartz, Koln,¨ Germany 3 Berlin Heidelberg New York Barcelona Hong Kong London Milan Paris Singapore Tokyo Editorial Policy The series Lecture Notes in Physics (LNP), founded in 1969, reports new developments in physics research and teaching -- quickly, informally but with a high quality. Manuscripts to be considered for publication are topical volumes consisting of a limited number of contributions, carefully edited and closely related to each other. Each contribution should contain at least partly original and previously unpublished material, be written in a clear, pedagogical style and aimed at a broader readership, especially graduate students and nonspecialist researchers wishing to familiarize themselves with the topic concerned. For this reason, traditional proceedings cannot be considered for this series though volumes to appear in this series are often based on material presented at conferences, workshops and schools (in exceptional cases the original papers and/or those not included in the printed book may be added on an accompanying CD ROM, together with the abstracts of posters and other material suitable for publication, e.g. large tables, colour pictures, program codes, etc.). Acceptance Aprojectcanonlybeacceptedtentativelyforpublication,byboththeeditorialboardandthe publisher, following thorough examination of the material submitted. The book proposal sent to the publisher should consist at least of a preliminary table of contents outlining the structureofthebooktogetherwithabstractsofallcontributionstobeincluded. -
Dynamical Relaxation to Quantum Equilibrium
Dynamical relaxation to quantum equilibrium Or, an account of Mike's attempt to write an entirely new computer code that doesn't do quantum Monte Carlo for the first time in years. ESDG, 10th February 2010 Mike Towler TCM Group, Cavendish Laboratory, University of Cambridge www.tcm.phy.cam.ac.uk/∼mdt26 and www.vallico.net/tti/tti.html [email protected] { Typeset by FoilTEX { 1 What I talked about a month ago (`Exchange, antisymmetry and Pauli repulsion', ESDG Jan 13th 2010) I showed that (1) the assumption that fermions are point particles with a continuous objective existence, and (2) the equations of non-relativistic QM, allow us to deduce: • ..that a mathematically well-defined ‘fifth force', non-local in character, appears to act on the particles and causes their trajectories to differ from the classical ones. • ..that this force appears to have its origin in an objectively-existing `wave field’ mathematically represented by the usual QM wave function. • ..that indistinguishability arguments are invalid under these assumptions; rather antisymmetrization implies the introduction of forces between particles. • ..the nature of spin. • ..that the action of the force prevents two fermions from coming into close proximity when `their spins are the same', and that in general, this mechanism prevents fermions from occupying the same quantum state. This is a readily understandable causal explanation for the Exclusion principle and for its otherwise inexplicable consequences such as `degeneracy pressure' in a white dwarf star. Furthermore, if assume antisymmetry of wave field not fundamental but develops naturally over the course of time, then can see character of reason for fermionic wave functions having symmetry behaviour they do. -
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. -
Signal-Locality in Hidden-Variables Theories
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Signal-Locality in Hidden-Variables Theories Antony Valentini1 Theoretical Physics Group, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ, England.2 Center for Gravitational Physics and Geometry, Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA. Augustus College, 14 Augustus Road, London SW19 6LN, England.3 We prove that all deterministic hidden-variables theories, that reproduce quantum theory for an ‘equilibrium’ distribution of hidden variables, give in- stantaneous signals at the statistical level for hypothetical ‘nonequilibrium en- sembles’. This generalises another property of de Broglie-Bohm theory. Assum- ing a certain symmetry, we derive a lower bound on the (equilibrium) fraction of outcomes at one wing of an EPR-experiment that change in response to a shift in the distant angular setting. We argue that the universe is in a special state of statistical equilibrium that hides nonlocality. PACS: 03.65.Ud; 03.65.Ta 1email: [email protected] 2Corresponding address. 3Permanent address. 1 Introduction: Bell’s theorem shows that, with reasonable assumptions, any deterministic hidden-variables theory behind quantum mechanics has to be non- local [1]. Specifically, for pairs of spin-1/2 particles in the singlet state, the outcomes of spin measurements at each wing must depend instantaneously on the axis of measurement at the other, distant wing. In this paper we show that the underlying nonlocality becomes visible at the statistical level for hypothet- ical ensembles whose distribution differs from that of quantum theory. -
An Introduction to Effective Field Theory
An Introduction to Effective Field Theory Thinking Effectively About Hierarchies of Scale c C.P. BURGESS i Preface It is an everyday fact of life that Nature comes to us with a variety of scales: from quarks, nuclei and atoms through planets, stars and galaxies up to the overall Universal large-scale structure. Science progresses because we can understand each of these on its own terms, and need not understand all scales at once. This is possible because of a basic fact of Nature: most of the details of small distance physics are irrelevant for the description of longer-distance phenomena. Our description of Nature’s laws use quantum field theories, which share this property that short distances mostly decouple from larger ones. E↵ective Field Theories (EFTs) are the tools developed over the years to show why it does. These tools have immense practical value: knowing which scales are important and why the rest decouple allows hierarchies of scale to be used to simplify the description of many systems. This book provides an introduction to these tools, and to emphasize their great generality illustrates them using applications from many parts of physics: relativistic and nonrelativistic; few- body and many-body. The book is broadly appropriate for an introductory graduate course, though some topics could be done in an upper-level course for advanced undergraduates. It should interest physicists interested in learning these techniques for practical purposes as well as those who enjoy the beauty of the unified picture of physics that emerges. It is to emphasize this unity that a broad selection of applications is examined, although this also means no one topic is explored in as much depth as it deserves. -
Soft Gravitons and the Flat Space Limit of Anti-Desitter Space
RUNHETC-2016-15, UTTG-18-16 Soft Gravitons and the Flat Space Limit of Anti-deSitter Space Tom Banks Department of Physics and NHETC Rutgers University, Piscataway, NJ 08854 E-mail: [email protected] Willy Fischler Department of Physics and Texas Cosmology Center University of Texas, Austin, TX 78712 E-mail: fi[email protected] Abstract We argue that flat space amplitudes for the process 2 n gravitons at center of mass → energies √s much less than the Planck scale, will coincide approximately with amplitudes calculated from correlators of a boundary CFT for AdS space of radius R LP , only ≫ when n < R/LP . For larger values of n in AdS space, insisting that all the incoming energy enters “the arena”[20] , implies the production of black holes, whereas there is no black hole production in the flat space amplitudes. We also argue, from unitarity, that flat space amplitudes for all n are necessary to reconstruct the complicated singularity arXiv:1611.05906v3 [hep-th] 8 Apr 2017 at zero momentum in the 2 2 amplitude, which can therefore not be reproduced as → the limit of an AdS calculation. Applying similar reasoning to amplitudes for real black hole production in flat space, we argue that unitarity of the flat space S-matrix cannot be assessed or inferred from properties of CFT correlators. 1 Introduction The study of the flat space limit of correlation functions in AdS/CFT was initiated by the work of Polchinski and Susskind[20] and continued in a host of other papers. Most of those papers agree with the contention, that the limit of Witten diagrams for CFT correlators smeared with appropriate test functions, for operators carrying vanishing angular momentum on the compact 1 space,1 converge to flat space S-matrix elements between states in Fock space. -
Quantum Computing in the De Broglie-Bohm Pilot-Wave Picture
Quantum Computing in the de Broglie-Bohm Pilot-Wave Picture Philipp Roser September 2010 Blackett Laboratory Imperial College London Submitted in partial fulfilment of the requirements for the degree of Master of Science of Imperial College London Supervisor: Dr. Antony Valentini Internal Supervisor: Prof. Jonathan Halliwell Abstract Much attention has been drawn to quantum computing and the expo- nential speed-up in computation the technology would be able to provide. Various claims have been made about what aspect of quantum mechan- ics causes this speed-up. Formulations of quantum computing have tradi- tionally been made in orthodox (Copenhagen) and sometimes many-worlds quantum mechanics. We will aim to understand quantum computing in terms of de Broglie-Bohm Pilot-Wave Theory by considering different sim- ple systems that may function as a basic quantum computer. We will provide a careful discussion of Pilot-Wave Theory and evaluate criticisms of the theory. We will assess claims regarding what causes the exponential speed-up in the light of our analysis and the fact that Pilot-Wave The- ory is perfectly able to account for the phenomena involved in quantum computing. I, Philipp Roser, hereby confirm that this dissertation is entirely my own work. Where other sources have been used, these have been clearly referenced. 1 Contents 1 Introduction 3 2 De Broglie-Bohm Pilot-Wave Theory 8 2.1 Motivation . 8 2.2 Two theories of pilot-waves . 9 2.3 The ensemble distribution and probability . 18 2.4 Measurement . 22 2.5 Spin . 26 2.6 Objections and open questions . 33 2.7 Pilot-Wave Theory, Many-Worlds and Many-Worlds in denial . -
Collective Coordinates for D-Branes 1 Introduction
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server UTTG-01-96 Collective Co ordinates for D-branes Willy Fischler, Sonia Paban and Moshe Rozali Theory Group, Department of Physics University of Texas, Austin, Texas 78712 Abstract We develop a formalism for the scattering o D-branes that includes collective co- ordinates. This allows a systematic expansion in the string coupling constant for such pro cesses, including a worldsheet calculation for the D-brane's mass. 1 Intro duction In the recent developments of string theory, solitons play a central role. For example, in the case of duality among various string theories, solitons of a weakly coupled string theory b ecome elementary excitations of the dual theory [1]. Another example, among many others, is the role of solitons in resolving singularities in compacti ed geometries, as they b ecome light[2]. In order to gain more insight in the various asp ects of these recent developments, it is imp ortant to understand the dynamics of solitons in the context of string theory.In this quest one of the to ols at our disp osal is the use of scattering involving these solitons. This includes the scattering of elementary string states o these solitons as well as the scattering among solitons. An imp ortant class of solitons that have emerged are D-branes [4]. In an in uential pap er [3]itwas shown that these D-branes carry R R charges, and are therefore a central ingredient in the aforementioned dualities. -
The Spirit and the Intellect: Lessons in Humility
BYU Studies Quarterly Volume 50 Issue 4 Article 6 12-1-2011 The Spirit and the Intellect: Lessons in Humility Duane Boyce Follow this and additional works at: https://scholarsarchive.byu.edu/byusq Recommended Citation Boyce, Duane (2011) "The Spirit and the Intellect: Lessons in Humility," BYU Studies Quarterly: Vol. 50 : Iss. 4 , Article 6. Available at: https://scholarsarchive.byu.edu/byusq/vol50/iss4/6 This Article is brought to you for free and open access by the Journals at BYU ScholarsArchive. It has been accepted for inclusion in BYU Studies Quarterly by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Boyce: The Spirit and the Intellect: Lessons in Humility The Spirit and the Intellect Lessons in Humility Duane Boyce “The only wisdom we can hope to acquire is the wisdom of humility: humility is endless.” —T. S. Eliot1 Whence Such Confidence? I have friends who see themselves as having intellectual problems with the gospel—with some spiritual matter or other. Interestingly, these friends all share the same twofold characteristic: they are confident they know a lot about spiritual topics, and they are confident they know a lot about various intellectual matters. This always interests me, because my experience is very different. I am quite struck by how much I don’t know about spiritual things and by how much I don’t know about anything else. The overwhelming feeling I get, both from thoroughly examining a scriptural subject (say, faith2) and from carefully studying an academic topic (for example, John Bell’s inequality theorem in physics), is the same—a profound recognition of how little I really know, and how significantly, on many topics, scholars who are more knowledgeable than I am disagree among themselves: in other words, I am surprised by how little they really know, too. -
King's Research Portal
King’s Research Portal DOI: 10.1088/1742-6596/631/1/012089 Document Version Publisher's PDF, also known as Version of record Link to publication record in King's Research Portal Citation for published version (APA): Sarkar, S. (2015). String theory backgrounds with torsion in the presence of fermions and implications for leptogenesis. Journal of Physics: Conference Series, 631(1), [012089]. 10.1088/1742-6596/631/1/012089 Citing this paper Please note that where the full-text provided on King's Research Portal is the Author Accepted Manuscript or Post-Print version this may differ from the final Published version. If citing, it is advised that you check and use the publisher's definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publisher's website for any subsequent corrections. General rights Copyright and moral rights for the publications made accessible in the Research Portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognize and abide by the legal requirements associated with these rights. •Users may download and print one copy of any publication from the Research Portal for the purpose of private study or research. •You may not further distribute the material or use it for any profit-making activity or commercial gain •You may freely distribute the URL identifying the publication in the Research Portal Take down policy If you believe that this document breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. -
Collective Coordinates for D-Branes
UTTG-01-96 Collective Coordinates for D-branes Willy Fischler, Sonia Paban and Moshe Rozali∗ Theory Group, Department of Physics University of Texas, Austin, Texas 78712 Abstract We develop a formalism for the scattering off D-branes that includes collective co- ordinates. This allows a systematic expansion in the string coupling constant for such processes, including a worldsheet calculation for the D-brane’s mass. 1 Introduction In the recent developments of string theory, solitons play a central role. For example, in the case of duality among various string theories, solitons of a weakly coupled string theory become elementary excitations of the dual theory [1]. Another example, among many others, is the role of solitons in resolving singularities in compactified geometries, as they become light [2]. In order to gain more insight in the various aspects of these recent developments, it is important to understand the dynamics of solitons in the context of string theory. In this quest one of the tools at our disposal is the use of scattering involving these solitons. This includes the scattering of elementary string states off these solitons as well as the arXiv:hep-th/9604014v2 11 Apr 1996 scattering among solitons. An important class of solitons that have emerged are D-branes [4]. In an influential paper [3] it was shown that these D-branes carry R R charges, − and are therefore a central ingredient in the aforementioned dualities. These objects are described by simple conformal field theories, which makes them particularly suited for explicit calculations. In this paper we use some of the preliminary ideas about collective coordinates de- veloped in a previous paper [5], to describe the scattering of elementary string states off D-branes. -
Copyright by Juan Felipe Pedraza Avella 2015
Copyright by Juan Felipe Pedraza Avella 2015 The Dissertation Committee for Juan Felipe Pedraza Avella certifies that this is the approved version of the following dissertation: Dynamics of asymptotically AdS spaces and holography Committee: Willy Fischler, Supervisor Jacques Distler Can Kilic Andrew Neitzke Sonia Paban Dynamics of asymptotically AdS spaces and holography by Juan Felipe Pedraza Avella, B.S., M.S. DISSERTATION Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY THE UNIVERSITY OF TEXAS AT AUSTIN August 2015 Dedicated to my family. Acknowledgments Many people contributed to the research presented in this thesis. I would like to start by thanking my supervisor, prof. Willy Fischler, for his excellent support and guidance over the past five years. I am also grateful to my collaborators: Cesar Ag´on,Tom Banks, Elena C´aceres,Mariano Cherni- coff, Brandon DiNunno, Mohammad Edalati, Bartomeu Fiol, Antonio Garc´ıa, Alberto G¨uijosa,Matthias Ihl, Niko Jokela, Arnab Kundu, Sandipan Kundu, Patricio Letelier,1 Fabio Lora, Phuc Nguyen, Paolo Ospina, Javier Ramos, Walter Tangarife and Di-Lun Yang. For all the time we spent discussing physics, which lead to many successful ideas [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]. Finally, I would like to thank my fellow students and the professors of the UT Theory Group, for sharing their vast knowledge in individual discussions, seminars and journal club meetings. This material is based upon work supported by the National Science Foundation under Grant PHY-1316033 and by the Texas Cosmology Center, which is supported by the College of Natural Sciences, the Department of As- tronomy at the University of Texas at Austin and the McDonald Observatory.