Time in Quantum Theory*
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Quantum Optics: an Introduction
The Himalayan Physics, Vol.1, No.1, May 2010 Quantum Optics: An Introduction Min Raj Lamsal Prithwi Narayan Campus, Pokhara Email: [email protected] Optics is the physics, which deals with the study of in electrodynamics gave beautiful and satisfactory nature of light, its propagation in different media description of the electromagnetic phenomena. At (including vacuum) & its interaction with different the same time, the kinetic theory of gases provided materials. Quantum is a packet of energy absorbed or a microscopic basis for the thermo dynamical emitted in the form of tiny packets called quanta. It properties of matter. Up to the end of the nineteenth means the amount of energy released or absorbed in century, the classical physics was so successful a physical process is always an integral multiple of and impressive in explaining physical phenomena a discrete unit of energy known as quantum which is that the scientists of that time absolutely believed also known as photon. Quantum Optics is a fi eld of that they were potentially capable of explaining all research in physics, dealing with the application of physical phenomena. quantum mechanics to phenomena involving light and its interactions with matter. However, the fi rst indication of inadequacy of the Physics in which majority of physical phenomena classical physics was seen in the beginning of the can be successfully described by using Newton’s twentieth century where it could not explain the laws of motion is called classical physics. In fact, the experimentally observed spectra of a blackbody classical physics includes the classical mechanics and radiation. In addition, the laws in classical physics the electromagnetic theory. -
Quantum Field Theory*
Quantum Field Theory y Frank Wilczek Institute for Advanced Study, School of Natural Science, Olden Lane, Princeton, NJ 08540 I discuss the general principles underlying quantum eld theory, and attempt to identify its most profound consequences. The deep est of these consequences result from the in nite number of degrees of freedom invoked to implement lo cality.Imention a few of its most striking successes, b oth achieved and prosp ective. Possible limitation s of quantum eld theory are viewed in the light of its history. I. SURVEY Quantum eld theory is the framework in which the regnant theories of the electroweak and strong interactions, which together form the Standard Mo del, are formulated. Quantum electro dynamics (QED), b esides providing a com- plete foundation for atomic physics and chemistry, has supp orted calculations of physical quantities with unparalleled precision. The exp erimentally measured value of the magnetic dip ole moment of the muon, 11 (g 2) = 233 184 600 (1680) 10 ; (1) exp: for example, should b e compared with the theoretical prediction 11 (g 2) = 233 183 478 (308) 10 : (2) theor: In quantum chromo dynamics (QCD) we cannot, for the forseeable future, aspire to to comparable accuracy.Yet QCD provides di erent, and at least equally impressive, evidence for the validity of the basic principles of quantum eld theory. Indeed, b ecause in QCD the interactions are stronger, QCD manifests a wider variety of phenomena characteristic of quantum eld theory. These include esp ecially running of the e ective coupling with distance or energy scale and the phenomenon of con nement. -
The Concept of Quantum State : New Views on Old Phenomena Michel Paty
The concept of quantum state : new views on old phenomena Michel Paty To cite this version: Michel Paty. The concept of quantum state : new views on old phenomena. Ashtekar, Abhay, Cohen, Robert S., Howard, Don, Renn, Jürgen, Sarkar, Sahotra & Shimony, Abner. Revisiting the Founda- tions of Relativistic Physics : Festschrift in Honor of John Stachel, Boston Studies in the Philosophy and History of Science, Dordrecht: Kluwer Academic Publishers, p. 451-478, 2003. halshs-00189410 HAL Id: halshs-00189410 https://halshs.archives-ouvertes.fr/halshs-00189410 Submitted on 20 Nov 2007 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. « The concept of quantum state: new views on old phenomena », in Ashtekar, Abhay, Cohen, Robert S., Howard, Don, Renn, Jürgen, Sarkar, Sahotra & Shimony, Abner (eds.), Revisiting the Foundations of Relativistic Physics : Festschrift in Honor of John Stachel, Boston Studies in the Philosophy and History of Science, Dordrecht: Kluwer Academic Publishers, 451-478. , 2003 The concept of quantum state : new views on old phenomena par Michel PATY* ABSTRACT. Recent developments in the area of the knowledge of quantum systems have led to consider as physical facts statements that appeared formerly to be more related to interpretation, with free options. -
The Philosophy and Physics of Time Travel: the Possibility of Time Travel
University of Minnesota Morris Digital Well University of Minnesota Morris Digital Well Honors Capstone Projects Student Scholarship 2017 The Philosophy and Physics of Time Travel: The Possibility of Time Travel Ramitha Rupasinghe University of Minnesota, Morris, [email protected] Follow this and additional works at: https://digitalcommons.morris.umn.edu/honors Part of the Philosophy Commons, and the Physics Commons Recommended Citation Rupasinghe, Ramitha, "The Philosophy and Physics of Time Travel: The Possibility of Time Travel" (2017). Honors Capstone Projects. 1. https://digitalcommons.morris.umn.edu/honors/1 This Paper is brought to you for free and open access by the Student Scholarship at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Honors Capstone Projects by an authorized administrator of University of Minnesota Morris Digital Well. For more information, please contact [email protected]. The Philosophy and Physics of Time Travel: The possibility of time travel Ramitha Rupasinghe IS 4994H - Honors Capstone Project Defense Panel – Pieranna Garavaso, Michael Korth, James Togeas University of Minnesota, Morris Spring 2017 1. Introduction Time is mysterious. Philosophers and scientists have pondered the question of what time might be for centuries and yet till this day, we don’t know what it is. Everyone talks about time, in fact, it’s the most common noun per the Oxford Dictionary. It’s in everything from history to music to culture. Despite time’s mysterious nature there are a lot of things that we can discuss in a logical manner. Time travel on the other hand is even more mysterious. -
A Measure of Change Brittany A
University of South Carolina Scholar Commons Theses and Dissertations Spring 2019 Time: A Measure of Change Brittany A. Gentry Follow this and additional works at: https://scholarcommons.sc.edu/etd Part of the Philosophy Commons Recommended Citation Gentry, B. A.(2019). Time: A Measure of Change. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/5247 This Open Access Dissertation is brought to you by Scholar Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Time: A Measure of Change By Brittany A. Gentry Bachelor of Arts Houghton College, 2009 ________________________________________________ Submitted in Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy in Philosophy College of Arts and Sciences University of South Carolina 2019 Accepted by Michael Dickson, Major Professor Leah McClimans, Committee Member Thomas Burke, Committee Member Alexander Pruss, Committee Member Cheryl L. Addy, Vice Provost and Dean of the Graduate School ©Copyright by Brittany A. Gentry, 2019 All Rights Reserved ii Acknowledgements I would like to thank Michael Dickson, my dissertation advisor, for extensive comments on numerous drafts over the last several years and for his patience and encouragement throughout this process. I would also like to thank my other committee members, Leah McClimans, Thomas Burke, and Alexander Pruss, for their comments and recommendations along the way. Finally, I am grateful to fellow students and professors at the University of South Carolina, the audience at the International Society for the Philosophy of Time conference at Wake Forest University, NC, and anonymous reviewers for helpful comments on various drafts of portions of this dissertation. -
Conceptual Problems in Quantum Electrodynamics: a Contemporary Historical-Philosophical Approach
Conceptual problems in quantum electrodynamics: a contemporary historical-philosophical approach (Redux version) PhD Thesis Mario Bacelar Valente Sevilla/Granada 2011 1 Conceptual problems in quantum electrodynamics: a contemporary historical-philosophical approach Dissertation submitted in fulfilment of the requirements for the Degree of Doctor by the Sevilla University Trabajo de investigación para la obtención del Grado de Doctor por la Universidad de Sevilla Mario Bacelar Valente Supervisors (Supervisores): José Ferreirós Dominguéz, Universidade de Sevilla. Henrik Zinkernagel, Universidade de Granada. 2 CONTENTS 1 Introduction 5 2 The Schrödinger equation and its interpretation Not included 3 The Dirac equation and its interpretation 8 1 Introduction 2 Before the Dirac equation: some historical remarks 3 The Dirac equation as a one-electron equation 4 The problem with the negative energy solutions 5 The field theoretical interpretation of Dirac’s equation 6 Combining results from the different views on Dirac’s equation 4 The quantization of the electromagnetic field and the vacuum state See Bacelar Valente, M. (2011). A Case for an Empirically Demonstrable Notion of the Vacuum in Quantum Electrodynamics Independent of Dynamical Fluctuations. Journal for General Philosophy of Science 42, 241–261. 5 The interaction of radiation and matter 28 1 introduction 2. Quantum electrodynamics as a perturbative approach 3 Possible problems to quantum electrodynamics: the Haag theorem and the divergence of the S-matrix series expansion 4 A note regarding the concept of vacuum in quantum electrodynamics 3 5 Conclusions 6 Aspects of renormalization in quantum electrodynamics 50 1 Introduction 2 The emergence of infinites in quantum electrodynamics 3 The submergence of infinites in quantum electrodynamics 4 Different views on renormalization 5 conclusions 7 The Feynman diagrams and virtual quanta See, Bacelar Valente, M. -
Time in Cosmology
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Philsci-Archive Time in Cosmology Craig Callender∗ C. D. McCoyy 21 August 2017 Readers familiar with the workhorse of cosmology, the hot big bang model, may think that cosmology raises little of interest about time. As cosmological models are just relativistic spacetimes, time is under- stood just as it is in relativity theory, and all cosmology adds is a few bells and whistles such as inflation and the big bang and no more. The aim of this chapter is to show that this opinion is not completely right...and may well be dead wrong. In our survey, we show how the hot big bang model invites deep questions about the nature of time, how inflationary cosmology has led to interesting new perspectives on time, and how cosmological speculation continues to entertain dramatically different models of time altogether. Together these issues indicate that the philosopher interested in the nature of time would do well to know a little about modern cosmology. Different claims about time have long been at the heart of cosmology. Ancient creation myths disagree over whether time is finite or infinite, linear or circular. This speculation led to Kant complaining in his famous antinomies that metaphysical reasoning about the nature of time leads to a “euthanasia of reason”. But neither Kant’s worry nor cosmology becoming a modern science succeeded in ending the speculation. Einstein’s first model of the universe portrays a temporally infinite universe, where space is edgeless and its material contents unchanging. -
Quantum Field Theory a Tourist Guide for Mathematicians
Mathematical Surveys and Monographs Volume 149 Quantum Field Theory A Tourist Guide for Mathematicians Gerald B. Folland American Mathematical Society http://dx.doi.org/10.1090/surv/149 Mathematical Surveys and Monographs Volume 149 Quantum Field Theory A Tourist Guide for Mathematicians Gerald B. Folland American Mathematical Society Providence, Rhode Island EDITORIAL COMMITTEE Jerry L. Bona Michael G. Eastwood Ralph L. Cohen Benjamin Sudakov J. T. Stafford, Chair 2010 Mathematics Subject Classification. Primary 81-01; Secondary 81T13, 81T15, 81U20, 81V10. For additional information and updates on this book, visit www.ams.org/bookpages/surv-149 Library of Congress Cataloging-in-Publication Data Folland, G. B. Quantum field theory : a tourist guide for mathematicians / Gerald B. Folland. p. cm. — (Mathematical surveys and monographs ; v. 149) Includes bibliographical references and index. ISBN 978-0-8218-4705-3 (alk. paper) 1. Quantum electrodynamics–Mathematics. 2. Quantum field theory–Mathematics. I. Title. QC680.F65 2008 530.1430151—dc22 2008021019 Copying and reprinting. Individual readers of this publication, and nonprofit libraries acting for them, are permitted to make fair use of the material, such as to copy a chapter for use in teaching or research. Permission is granted to quote brief passages from this publication in reviews, provided the customary acknowledgment of the source is given. Republication, systematic copying, or multiple reproduction of any material in this publication is permitted only under license from the American Mathematical Society. Requests for such permission should be addressed to the Acquisitions Department, American Mathematical Society, 201 Charles Street, Providence, Rhode Island 02904-2294 USA. Requests can also be made by e-mail to [email protected]. -
SPACE, TIME, and (How They) MATTER: a Discussion of Some Metaphysical Insights About the Nature of Space and Time Provided by Our Best Fundamental Physical Theories
SPACE, TIME, AND (how they) MATTER: A Discussion of Some Metaphysical Insights about the Nature of Space and Time Provided by Our Best Fundamental Physical Theories Valia Allori Northern Illinois University Forthcoming in: J. Statchel, G.C. Ghirardi (eds.). Space, Time, and Frontiers of Human Understanding. Springer-Verlag Abstract This paper is a brief (and hopelessly incomplete) non-standard introduction to the philosophy of space and time. It is an introduction because I plan to give an overview of what I consider some of the main questions about space and time: Is space a substance over and above matter? How many dimensions does it have? Is space-time fundamental or emergent? Does time have a direction? Does time even exist? Nonetheless, this introduction is not standard because I conclude the discussion by presenting the material with an original spin, guided by a particular understanding of fundamental physical theories, the so-called primitive ontology approach. 1. Introduction Scientific realists believe that our best scientific theories could be used as reliable guides to understand what the world is like. First, they tell us about the nature of matter: for instance, matter can be made of particles, or two-dimensional strings, or continuous fields. In addition, whatever matter fundamentally is, it seems there is matter in space, which moves in time. The topic of this paper is what our best physical theories tell us about the nature of space and time. I will start in the next section with the traditional debate concerning the question of whether space is itself a substance or not. -
The Nature and Origin of Time-Asymmetric Spacetime Structures*
The nature and origin of time-asymmetric spacetime structures* H. D. Zeh (University of Heidelberg) www.zeh-hd.de Abstract: Time-asymmetric spacetime structures, in particular those representing black holes and the expansion of the universe, are intimately related to other arrows of time, such as the second law and the retardation of radiation. The nature of the quantum ar- row, often attributed to a collapse of the wave function, is essential, in particular, for understanding the much discussed "black hole information loss paradox". However, this paradox assumes a new form and might not even occur in a consistent causal treatment that would prevent the formation of horizons and singularities. A “master arrow”, which combines all arrows of time, does not have to be identified with the direction of a formal time parameter that serves to define the dynamics as a succes- sion of global states (a trajectory in configuration or Hilbert space). It may even change direction with respect to a fundamental physical clock, such as the cosmic expansion parameter if this was formally extended either into a future contraction era or to nega- tive "pre-big-bang" values. 1 Introduction Since gravity is attractive, most gravitational phenomena are asymmetric in time: ob- jects fall down or contract under the influence of gravity. In General Relativity, this asymmetry leads to drastically asymmetric spacetime structures, such as future hori- zons and future singularities as properties of black holes. However, since the relativistic and nonrelativistic laws of gravitation are symmetric under time reversal, all time asymmetries must arise as consequences of specific (only seemingly "normal") initial conditions, for example a situation of rest that can be prepared by means of other ar- * arXiv:1012.4708v11. -
Time Really Exists! the Evolving Block Universe Volume 7
Time really exists! Volume 7 The evolving block universe Summer 2014 George Ellis journal homepage Department of Mathematics, University of Cape Town, Rondebosch 7701, Cape www.euresisjournal.org Town, South Africa. [email protected] Abstract My starting point is the question, did it make sense for the Planck team to announce the present age of the universe? This talk will propose that it did, because spacetime is an evolving block universe, with the present being the future boundary of a spacetime which steadily extends into the future as time progresses. The present separates the past (which already exists) from the future (which does not yet exist, and is indeterminate because of foundational quantum uncertainty). There are some technical aspects to this namely (1) simultaneity has no physical import, it is a purely psychological construct, (2) one can define unique surfaces of constant time in a non-local geometric way(and show how this relates to the standard ADM formalism), (3) this proposal solves the chronology protection problem (it prevents existence of closed timelike lines). In this context, (4) the arrow of time is distinguished from the direction of time, which is non-locally defined in the evolving block universe context. 1. Prolog There are fossils in the Karoo National Park, South Africa, from amazing extinct wildlife that once thrived in the ancient Karoo during the Late Permian Period. The curator explained as we walked round, \That the skeleton is 255 million and 23 years old!" Amazed, we asked how he knew this. He said \When I came here 23 years ago, it was 255 million years old". -
The Philosophy Behind Quantum Gravity
The Philosophy behind Quantum Gravity Henrik Zinkernagel Department of Philosophy, Campus de Cartuja, 18071, University of Granada, Spain. [email protected] Published in Theoria - An International Journal for Theory, History and Foundations of Science (San Sebastián, Spain), Vol. 21/3, 2006, pp. 295-312. Abstract This paper investigates some of the philosophical and conceptual issues raised by the search for a quantum theory of gravity. It is critically discussed whether such a theory is necessary in the first place, and how much would be accomplished if it is eventually constructed. I argue that the motivations behind, and expectations to, a theory of quantum gravity are entangled with central themes in the philosophy of science, in particular unification, reductionism, and the interpretation of quantum mechanics. I further argue that there are –contrary to claims made on behalf of string theory –no good reasons to think that a quantum theory of gravity, if constructed, will provide a theory of everything, that is, a fundamental theory from which all physics in principle can be derived. 1. Introduction One of the outstanding tasks in fundamental physics, according to many theoretical physicists, is the construction of a quantum theory of gravity. The so far unsuccessful attempt to construct such a theory is an attempt to unify Einstein's general theory of relativity with quantum theory (or quantum field theory). While quantum gravity aims to describe everything in the universe in terms of quantum theory, the purpose of the closely related project of quantum cosmology is to describe even the universe as a whole as a quantum system.