Entropy, Decoherence and Spacetime Splitting
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Quaternions and Cli Ord Geometric Algebras
Quaternions and Cliord Geometric Algebras Robert Benjamin Easter First Draft Edition (v1) (c) copyright 2015, Robert Benjamin Easter, all rights reserved. Preface As a rst rough draft that has been put together very quickly, this book is likely to contain errata and disorganization. The references list and inline citations are very incompete, so the reader should search around for more references. I do not claim to be the inventor of any of the mathematics found here. However, some parts of this book may be considered new in some sense and were in small parts my own original research. Much of the contents was originally written by me as contributions to a web encyclopedia project just for fun, but for various reasons was inappropriate in an encyclopedic volume. I did not originally intend to write this book. This is not a dissertation, nor did its development receive any funding or proper peer review. I oer this free book to the public, such as it is, in the hope it could be helpful to an interested reader. June 19, 2015 - Robert B. Easter. (v1) [email protected] 3 Table of contents Preface . 3 List of gures . 9 1 Quaternion Algebra . 11 1.1 The Quaternion Formula . 11 1.2 The Scalar and Vector Parts . 15 1.3 The Quaternion Product . 16 1.4 The Dot Product . 16 1.5 The Cross Product . 17 1.6 Conjugates . 18 1.7 Tensor or Magnitude . 20 1.8 Versors . 20 1.9 Biradials . 22 1.10 Quaternion Identities . 23 1.11 The Biradial b/a . -
Scientific Contacts of Polish Physicists with Albert Einstein
The Global and the Local: The History of Science and the Cultural Integration of Europe. nd Proceedings of the 2 ICESHS (Cracow, Poland, September 6–9, 2006) / Ed. by M. Kokowski. Bronisław Średniawa * Scientific contacts of Polish physicists with Albert Einstein Abstract Scientific relations of Polish physicists, living in Poland and on emigration,with Albert Einstein, in the first half of 20th century are presented. Two Polish physicists, J. Laub and L. Infeld, were Einstein’s collaborators. The exchange of letters between M. Smoluchowski and Einstein contributed essentially to the solution of the problem of density fluctuations. S Loria, J. Kowalski, W. Natanson, M. Wolfke and L. Silberstein led scientific discussions with Einstein. Marie Skłodowska-Curie collaborated with Einstein in the Commission of Intelectual Cooperation of the Ligue of Nations. Einstein proposed scientific collaboration to M. Mathisson, but because of the breakout of the 2nd World War and Mathisson’s death their collaboration could not be realised. Contacts of Polish physicists with Einstein contributed to the development of relativity in Poland. (1) Introduction Many Polish physicists of older generation, who were active in Polish universities and abroad before the First World War or in the interwar period, had personal contacts with Einstein or exchanged letters with him. Contacts of Polish physicists with Einstein certainly inspired some Polish theoreticians to scientific work in relativity. These contacts encouraged also Polish physicists to make effort in the domain of popularization of relativity and of the progress of physics in the twenties and thirties. We can therefore say that the contacts of Polish physicists with Einstein contributed to the development of theoretical physics in Poland. -
International Centre for Theoretical Physics
:L^ -^ . ::, i^C IC/89/126 INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS NEW SPACETIME SUPERALGEBRAS AND THEIR KAC-MOODY EXTENSION Eric Bergshoeff and Ergin Sezgin INTERNATIONAL ATOMIC ENERGY AGENCY UNITED NATIONS EDUCATIONAL. SCIENTIFIC AND CULTURAL ORGANIZATION 1989 MIRAMARE - TRIESTE IC/89/I2G It is well known that supcrslrings admit two different kinds of formulations as far as International Atomic Energy Agency llieir siipcrsytnmclry properties arc concerned. One of them is the Ncveu-Sdwarz-tUmond and (NSIt) formulation [I] in which the world-sheet supcrsymmclry is manifest but spacetimn United Nations Educational Scientific and Cultural Organization supcrsymmclry is not. In this formulation, spacctimc supcrsymmctry arises as a consequence of Glbzzi-Schcrk-Olive (GSO) projections (2J in the Hilbcrt space. The field equations of INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS the world-sheet graviton and gravilino arc the constraints which obey the super-Virasoro algebra. In the other formulation, due to Green and Schwarz (GS) [3|, the spacrtimc super- symmetry is manifest but the world-sheet supersymmclry is not. In this case, the theory lias an interesting local world-sheet symmetry, known as K-symmetry, first discovered by NEW SPACETIME SUPERALGEBRAS AND THEIR KAC-MOODY EXTENSION Sicgcl [4,5) for the superparticlc, and later generalized by Green and Schwarz [3] for super- strings. In a light-cone gauge, a combination of the residual ic-symmetry and rigid spacetime supcrsyininetry fuse together to give rise to an (N=8 or 1G) rigid world-sheet supersymmclry. Eric BergflliocIT The two formulations are essentially equivalent in the light-cone gauge [6,7]. How- Theory Division, CERN, 1211 Geneva 23, Switzerland ever, for many purposes it is desirable to have a covariant quantization scheme. -
Sedeonic Theory of Massive Fields
Sedeonic theory of massive fields Sergey V. Mironov and Victor L. Mironov∗ Institute for physics of microstructures RAS, Nizhniy Novgorod, Russia (Submitted on August 5, 2013) Abstract In the present paper we develop the description of massive fields on the basis of space-time algebra of sixteen-component sedeons. The generalized sedeonic second-order equation for the potential of baryon field is proposed. It is shown that this equation can be reformulated in the form of a system of Maxwell-like equations for the field intensities. We calculate the baryonic fields in the simple model of point baryon charge and obtain the expression for the baryon- baryon interaction energy. We also propose the generalized sedeonic first-order equation for the potential of lepton field and calculate the energies of lepton-lepton and lepton-baryon interactions. Introduction Historically, the first theory of nuclear forces based on hypothesis of one-meson exchange has been formulated by Hideki Yukawa in 1935 [1]. In fact, he postulated a nonhomogeneous equation for the scalar field similar to the Klein-Gordon equation, whose solution is an effective short-range potential (so-called Yukawa potential). This theory clarified the short-ranged character of nuclear forces and was successfully applied to the explaining of low-energy nucleon-nucleon scattering data and properties of deuteron [2]. Afterwards during 1950s - 1990s many-meson exchange theories and phenomenological approach based on the effective nucleon potentials were proposed for the description of few-nucleon systems and intermediate-range nucleon interactions [3-11]. Nowadays the main fundamental concepts of nuclear force theory are developed in the frame of quantum chromodynamics (so-called effective field theory [13-15], see also reviews [16,17]) however, the meson theories and the effective potential approaches still play an important role for experimental data analysis in nuclear physics [18, 19]. -
SPINORS and SPACE–TIME ANISOTROPY
Sergiu Vacaru and Panayiotis Stavrinos SPINORS and SPACE{TIME ANISOTROPY University of Athens ————————————————— c Sergiu Vacaru and Panyiotis Stavrinos ii - i ABOUT THE BOOK This is the first monograph on the geometry of anisotropic spinor spaces and its applications in modern physics. The main subjects are the theory of grav- ity and matter fields in spaces provided with off–diagonal metrics and asso- ciated anholonomic frames and nonlinear connection structures, the algebra and geometry of distinguished anisotropic Clifford and spinor spaces, their extension to spaces of higher order anisotropy and the geometry of gravity and gauge theories with anisotropic spinor variables. The book summarizes the authors’ results and can be also considered as a pedagogical survey on the mentioned subjects. ii - iii ABOUT THE AUTHORS Sergiu Ion Vacaru was born in 1958 in the Republic of Moldova. He was educated at the Universities of the former URSS (in Tomsk, Moscow, Dubna and Kiev) and reveived his PhD in theoretical physics in 1994 at ”Al. I. Cuza” University, Ia¸si, Romania. He was employed as principal senior researcher, as- sociate and full professor and obtained a number of NATO/UNESCO grants and fellowships at various academic institutions in R. Moldova, Romania, Germany, United Kingdom, Italy, Portugal and USA. He has published in English two scientific monographs, a university text–book and more than hundred scientific works (in English, Russian and Romanian) on (super) gravity and string theories, extra–dimension and brane gravity, black hole physics and cosmolgy, exact solutions of Einstein equations, spinors and twistors, anistoropic stochastic and kinetic processes and thermodynamics in curved spaces, generalized Finsler (super) geometry and gauge gravity, quantum field and geometric methods in condensed matter physics. -
SEMISIMPLE WEAKLY SYMMETRIC PSEUDO–RIEMANNIAN MANIFOLDS 1. Introduction There Have Been a Number of Important Extensions of Th
SEMISIMPLE WEAKLY SYMMETRIC PSEUDO{RIEMANNIAN MANIFOLDS ZHIQI CHEN AND JOSEPH A. WOLF Abstract. We develop the classification of weakly symmetric pseudo{riemannian manifolds G=H where G is a semisimple Lie group and H is a reductive subgroup. We derive the classification from the cases where G is compact, and then we discuss the (isotropy) representation of H on the tangent space of G=H and the signature of the invariant pseudo{riemannian metric. As a consequence we obtain the classification of semisimple weakly symmetric manifolds of Lorentz signature (n − 1; 1) and trans{lorentzian signature (n − 2; 2). 1. Introduction There have been a number of important extensions of the theory of riemannian symmetric spaces. Weakly symmetric spaces, introduced by A. Selberg [8], play key roles in number theory, riemannian geometry and harmonic analysis. See [11]. Pseudo{riemannian symmetric spaces, including semisimple symmetric spaces, play central but complementary roles in number theory, differential geometry and relativity, Lie group representation theory and harmonic analysis. Much of the activity there has been on the Lorentz cases, which are of particular interest in physics. Here we study the classification of weakly symmetric pseudo{ riemannian manifolds G=H where G is a semisimple Lie group and H is a reductive subgroup. We apply the result to obtain explicit listings for metrics of riemannian (Table 5.1), lorentzian (Table 5.2) and trans{ lorentzian (Table 5.3) signature. The pseudo{riemannian symmetric case was analyzed extensively in the classical paper of M. Berger [1]. Our analysis in the weakly symmetric setting starts with the classifications of Kr¨amer[6], Brion [2], Mikityuk [7] and Yakimova [16, 17] for the weakly symmetric riemannian manifolds. -
Should Metric Signature Matter in Clifford Algebra Formulations Of
Should Metric Signature Matter in Clifford Algebra Formulations of Physical Theories? ∗ William M. Pezzaglia Jr. † Department of Physics Santa Clara University Santa Clara, CA 95053 John J. Adams ‡ P.O. Box 808, L-399 Lawrence Livermore National Laboratory Livermore, CA 94550 February 4, 2008 Abstract Standard formulation is unable to distinguish between the (+++−) and (−−−+) spacetime metric signatures. However, the Clifford algebras associated with each are inequivalent, R(4) in the first case (real 4 by 4 matrices), H(2) in the latter (quaternionic 2 by 2). Multivector reformu- lations of Dirac theory by various authors look quite inequivalent pending the algebra assumed. It is not clear if this is mere artifact, or if there is a right/wrong choice as to which one describes reality. However, recently it has been shown that one can map from one signature to the other using a tilt transformation[8]. The broader question is that if the universe is arXiv:gr-qc/9704048v1 17 Apr 1997 signature blind, then perhaps a complete theory should be manifestly tilt covariant. A generalized multivector wave equation is proposed which is fully signature invariant in form, because it includes all the components of the algebra in the wavefunction (instead of restricting it to half) as well as all the possibilities for interaction terms. Summary of talk at the Special Session on Octonions and Clifford Algebras, at the 1997 Spring Western Sectional Meeting of the American Mathematical Society, Oregon State University, Corvallis, OR, 19-20 April 1997. ∗anonymous ftp://www.clifford.org/clf-alg/preprints/1995/pezz9502.latex †Email: [email protected] or [email protected] ‡Email: [email protected] 1 I. -
Quantum Gravity, Field Theory and Signatures of Noncommutative Spacetime
HWM–09–5 EMPG–09–10 Quantum Gravity, Field Theory and Signatures of Noncommutative Spacetime1 Richard J. Szabo Department of Mathematics Heriot-Watt University Colin Maclaurin Building, Riccarton, Edinburgh EH14 4AS, U.K. and Maxwell Institute for Mathematical Sciences, Edinburgh, U.K. Email: [email protected] Abstract A pedagogical introduction to some of the main ideas and results of field theories on quantized spacetimes is presented, with emphasis on what such field theories may teach us about the problem of quantizing gravity. We examine to what extent noncommutative gauge theories may be regarded as gauge theories of gravity. UV/IR mixing is explained in detail and we describe its relations to renormalization, to gravitational dynamics, and to deformed dispersion relations arXiv:0906.2913v3 [hep-th] 5 Oct 2009 in models of quantum spacetime of interest in string theory and in doubly special relativity. We also discuss some potential experimental probes of spacetime noncommutativity. 1Based on Plenary Lecture delivered at the XXIX Encontro Nacional de F´ısica de Part´ıculas e Campos, S˜ao Louren¸co, Brasil, September 22–26, 2008. Contents 1 Introduction 1 2 Spacetime quantization 3 2.1 Snyder’sspacetime ............................... ...... 3 2.2 κ-Minkowskispacetime. .. .. .. .. .. .. .. .. .. ... 4 2.3 Three-dimensional quantum gravity . .......... 5 2.4 Spacetime uncertainty principle . ........... 6 2.5 Physicsinstrongmagneticfields . ......... 7 2.6 Noncommutative geometry in string theory . ........... 8 3 Field theory on quantized spacetimes 9 3.1 Formalism....................................... ... 9 3.2 UV/IRmixing ..................................... 10 3.3 Renormalization ................................. ..... 12 4 Noncommutative gauge theory of gravity 14 4.1 Gaugeinteractions ............................... ...... 14 4.2 Gravity in noncommutative gauge theories . -
The Dirac Equation in General Relativity, a Guide for Calculations
The Dirac equation in general relativity A guide for calculations Peter Collas1 and David Klein2 (September 7, 2018) Abstract In these informal lecture notes we outline different approaches used in doing calculations involving the Dirac equation in curved spacetime. We have tried to clarify the subject by carefully pointing out the various con- ventions used and by including several examples from textbooks and the existing literature. In addition some basic material has been included in the appendices. It is our hope that graduate students and other re- searchers will find these notes useful. arXiv:1809.02764v1 [gr-qc] 8 Sep 2018 1Department of Physics and Astronomy, California State University, Northridge, Northridge, CA 91330-8268. Email: [email protected]. 2Department of Mathematics and Interdisciplinary Research Institute for the Sci- ences, California State University, Northridge, Northridge, CA 91330-8313. Email: [email protected]. Contents 1 The spinorial covariant derivative3 1.1 The Fock-Ivanenko coefficients . .3 1.2 The Ricci rotation coefficient approach . .8 1.3 The electromagnetic interaction . .9 1.4 The Newman-Penrose formalism . 10 2 Examples 14 2.1 Schwarzschild spacetime N-P . 14 2.2 Schwarzschild spacetime F-I . 16 2.3 Nonfactorizable metric . 18 2.4 de Sitter spacetime, Fermi coordinates . 19 3 The Dirac equation in (1+1) GR 23 3.1 Introduction to (1+1) . 23 3.2 The Dirac equation in the Milne universe . 24 4 Scalar product 28 4.1 Conservation of j in SR . 28 4.2 The current density in GR . 29 4.3 The Scalar product in SR . -
Quantum/Classical Interface: Fermion Spin
Quantum/Classical Interface: Fermion Spin W. E. Baylis, R. Cabrera, and D. Keselica Department of Physics, University of Windsor Although intrinsic spin is usually viewed as a purely quantum property with no classical ana- log, we present evidence here that fermion spin has a classical origin rooted in the geometry of three-dimensional physical space. Our approach to the quantum/classical interface is based on a formulation of relativistic classical mechanics that uses spinors. Spinors and projectors arise natu- rally in the Clifford’s geometric algebra of physical space and not only provide powerful tools for solving problems in classical electrodynamics, but also reproduce a number of quantum results. In particular, many properites of elementary fermions, as spin-1/2 particles, are obtained classically and relate spin, the associated g-factor, its coupling to an external magnetic field, and its magnetic moment to Zitterbewegung and de Broglie waves. The relationship is further strengthened by the fact that physical space and its geometric algebra can be derived from fermion annihilation and creation operators. The approach resolves Pauli’s argument against treating time as an operator by recognizing phase factors as projected rotation operators. I. INTRODUCTION The intrinsic spin of elementary fermions like the electron is traditionally viewed as an essentially quantum property with no classical counterpart.[1, 2] Its two-valued nature, the fact that any measurement of the spin in an arbitrary direction gives a statistical distribution of either “spin up” or “spin down” and nothing in between, together with the commutation relation between orthogonal components, is responsible for many of its “nonclassical” properties. -
Post-Linear Metric of a Compact Source of Matter
Post-linear metric of a compact source of matter Sven Zschocke Institute of Planetary Geodesy - Lohrmann Observatory, Dresden Technical University, Helmholtzstrasse 10, D-01069 Dresden, Germany The Multipolar Post-Minkowskian (MPM) formalism represents an approach for determining the metric density in the exterior of a compact source of matter. In the MPM formalism the metric density is given in harmonic coordinates and in terms of symmetric tracefree (STF) multipoles. In this investigation, the post-linear metric density of this formalism is used in order to determine the post-linear metric tensor in the exterior of a compact source of matter. The metric tensor is given in harmonic coordinates and in terms of STF multipoles. The post-linear metric coefficients are associated with an integration procedure. The integration of these post-linear metric coefficients is performed explicitly for the case of a stationary source, where the first multipoles (monopole and quadrupole) of the source are taken into account. These studies are a requirement for further investigations in the theory of light propagation aiming at highly precise astrometric measurements in the solar system, where the post-linear coefficients of the metric tensor of solar system bodies become relevant. I. INTRODUCTION Our motivation to consider the post-linear term in the metric perturbation (2) is triggered by the rapid progress The field equations of gravity [1, 2] represent a set in astrometric science, which has recently made the im- of ten coupled non-linear partial differential equations pressive advancement from the milli-arcsecond level [14{ 16] to the micro-arcsecond level [17{21] in angular mea- for the ten components of the metric tensor gαβ which governs the geometry of space-time. -
Relativistic Spacetime Structure
Relativistic Spacetime Structure Samuel C. Fletcher∗ Department of Philosophy University of Minnesota, Twin Cities & Munich Center for Mathematical Philosophy Ludwig Maximilian University of Munich August 12, 2019 Abstract I survey from a modern perspective what spacetime structure there is according to the general theory of relativity, and what of it determines what else. I describe in some detail both the “standard” and various alternative answers to these questions. Besides bringing many underexplored topics to the attention of philosophers of physics and of science, metaphysicians of science, and foundationally minded physicists, I also aim to cast other, more familiar ones in a new light. 1 Introduction and Scope In the broadest sense, spacetime structure consists in the totality of relations between events and processes described in a spacetime theory, including distance, duration, motion, and (more gener- ally) change. A spacetime theory can attribute more or less such structure, and some parts of that structure may determine other parts. The nature of these structures and their relations of determi- nation bear on the interpretation of the theory—what the world would be like if the theory were true (North, 2009). For example, the structures of spacetime might be taken as its ontological or conceptual posits, and the determination relations might indicate which of these structures is more fundamental (North, 2018). Different perspectives on these questions might also reveal structural similarities with other spacetime theories, providing the resources to articulate how the picture of the world that that theory provides is different (if at all) from what came before, and might be different from what is yet to come.1 ∗Juliusz Doboszewski, Laurenz Hudetz, Eleanor Knox, J.