New Spacetimes for Rotating Dust in (2 + 1)-Dimensional General Relativity
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A Mathematical Derivation of the General Relativistic Schwarzschild
A Mathematical Derivation of the General Relativistic Schwarzschild Metric An Honors thesis presented to the faculty of the Departments of Physics and Mathematics East Tennessee State University In partial fulfillment of the requirements for the Honors Scholar and Honors-in-Discipline Programs for a Bachelor of Science in Physics and Mathematics by David Simpson April 2007 Robert Gardner, Ph.D. Mark Giroux, Ph.D. Keywords: differential geometry, general relativity, Schwarzschild metric, black holes ABSTRACT The Mathematical Derivation of the General Relativistic Schwarzschild Metric by David Simpson We briefly discuss some underlying principles of special and general relativity with the focus on a more geometric interpretation. We outline Einstein’s Equations which describes the geometry of spacetime due to the influence of mass, and from there derive the Schwarzschild metric. The metric relies on the curvature of spacetime to provide a means of measuring invariant spacetime intervals around an isolated, static, and spherically symmetric mass M, which could represent a star or a black hole. In the derivation, we suggest a concise mathematical line of reasoning to evaluate the large number of cumbersome equations involved which was not found elsewhere in our survey of the literature. 2 CONTENTS ABSTRACT ................................. 2 1 Introduction to Relativity ...................... 4 1.1 Minkowski Space ....................... 6 1.2 What is a black hole? ..................... 11 1.3 Geodesics and Christoffel Symbols ............. 14 2 Einstein’s Field Equations and Requirements for a Solution .17 2.1 Einstein’s Field Equations .................. 20 3 Derivation of the Schwarzschild Metric .............. 21 3.1 Evaluation of the Christoffel Symbols .......... 25 3.2 Ricci Tensor Components ................. -
The Penrose and Hawking Singularity Theorems Revisited
Classical singularity thms. Interlude: Low regularity in GR Low regularity singularity thms. Proofs Outlook The Penrose and Hawking Singularity Theorems revisited Roland Steinbauer Faculty of Mathematics, University of Vienna Prague, October 2016 The Penrose and Hawking Singularity Theorems revisited 1 / 27 Classical singularity thms. Interlude: Low regularity in GR Low regularity singularity thms. Proofs Outlook Overview Long-term project on Lorentzian geometry and general relativity with metrics of low regularity jointly with `theoretical branch' (Vienna & U.K.): Melanie Graf, James Grant, G¨untherH¨ormann,Mike Kunzinger, Clemens S¨amann,James Vickers `exact solutions branch' (Vienna & Prague): Jiˇr´ıPodolsk´y,Clemens S¨amann,Robert Svarcˇ The Penrose and Hawking Singularity Theorems revisited 2 / 27 Classical singularity thms. Interlude: Low regularity in GR Low regularity singularity thms. Proofs Outlook Contents 1 The classical singularity theorems 2 Interlude: Low regularity in GR 3 The low regularity singularity theorems 4 Key issues of the proofs 5 Outlook The Penrose and Hawking Singularity Theorems revisited 3 / 27 Classical singularity thms. Interlude: Low regularity in GR Low regularity singularity thms. Proofs Outlook Table of Contents 1 The classical singularity theorems 2 Interlude: Low regularity in GR 3 The low regularity singularity theorems 4 Key issues of the proofs 5 Outlook The Penrose and Hawking Singularity Theorems revisited 4 / 27 Theorem (Pattern singularity theorem [Senovilla, 98]) In a spacetime the following are incompatible (i) Energy condition (iii) Initial or boundary condition (ii) Causality condition (iv) Causal geodesic completeness (iii) initial condition ; causal geodesics start focussing (i) energy condition ; focussing goes on ; focal point (ii) causality condition ; no focal points way out: one causal geodesic has to be incomplete, i.e., : (iv) Classical singularity thms. -
Physics 200 Problem Set 7 Solution Quick Overview: Although Relativity Can Be a Little Bewildering, This Problem Set Uses Just A
Physics 200 Problem Set 7 Solution Quick overview: Although relativity can be a little bewildering, this problem set uses just a few ideas over and over again, namely 1. Coordinates (x; t) in one frame are related to coordinates (x0; t0) in another frame by the Lorentz transformation formulas. 2. Similarly, space and time intervals (¢x; ¢t) in one frame are related to inter- vals (¢x0; ¢t0) in another frame by the same Lorentz transformation formu- las. Note that time dilation and length contraction are just special cases: it is time-dilation if ¢x = 0 and length contraction if ¢t = 0. 3. The spacetime interval (¢s)2 = (c¢t)2 ¡ (¢x)2 between two events is the same in every frame. 4. Energy and momentum are always conserved, and we can make e±cient use of this fact by writing them together in an energy-momentum vector P = (E=c; p) with the property P 2 = m2c2. In particular, if the mass is zero then P 2 = 0. 1. The earth and sun are 8.3 light-minutes apart. Ignore their relative motion for this problem and assume they live in a single inertial frame, the Earth-Sun frame. Events A and B occur at t = 0 on the earth and at 2 minutes on the sun respectively. Find the time di®erence between the events according to an observer moving at u = 0:8c from Earth to Sun. Repeat if observer is moving in the opposite direction at u = 0:8c. Answer: According to the formula for a Lorentz transformation, ³ u ´ 1 ¢tobserver = γ ¢tEarth-Sun ¡ ¢xEarth-Sun ; γ = p : c2 1 ¡ (u=c)2 Plugging in the numbers gives (notice that the c implicit in \light-minute" cancels the extra factor of c, which is why it's nice to measure distances in terms of the speed of light) 2 min ¡ 0:8(8:3 min) ¢tobserver = p = ¡7:7 min; 1 ¡ 0:82 which means that according to the observer, event B happened before event A! If we reverse the sign of u then 2 min + 0:8(8:3 min) ¢tobserver 2 = p = 14 min: 1 ¡ 0:82 2. -
Closed Timelike Curves, Singularities and Causality: a Survey from Gödel to Chronological Protection
Closed Timelike Curves, Singularities and Causality: A Survey from Gödel to Chronological Protection Jean-Pierre Luminet Aix-Marseille Université, CNRS, Laboratoire d’Astrophysique de Marseille , France; Centre de Physique Théorique de Marseille (France) Observatoire de Paris, LUTH (France) [email protected] Abstract: I give a historical survey of the discussions about the existence of closed timelike curves in general relativistic models of the universe, opening the physical possibility of time travel in the past, as first recognized by K. Gödel in his rotating universe model of 1949. I emphasize that journeying into the past is intimately linked to spacetime models devoid of timelike singularities. Since such singularities arise as an inevitable consequence of the equations of general relativity given physically reasonable assumptions, time travel in the past becomes possible only when one or another of these assumptions is violated. It is the case with wormhole-type solutions. S. Hawking and other authors have tried to save the paradoxical consequences of time travel in the past by advocating physical mechanisms of chronological protection; however, such mechanisms remain presently unknown, even when quantum fluctuations near horizons are taken into account. I close the survey by a brief and pedestrian discussion of Causal Dynamical Triangulations, an approach to quantum gravity in which causality plays a seminal role. Keywords: time travel; closed timelike curves; singularities; wormholes; Gödel’s universe; chronological protection; causal dynamical triangulations 1. Introduction In 1949, the mathematician and logician Kurt Gödel, who had previously demonstrated the incompleteness theorems that broke ground in logic, mathematics, and philosophy, became interested in the theory of general relativity of Albert Einstein, of which he became a close colleague at the Institute for Advanced Study at Princeton. -
Light Rays, Singularities, and All That
Light Rays, Singularities, and All That Edward Witten School of Natural Sciences, Institute for Advanced Study Einstein Drive, Princeton, NJ 08540 USA Abstract This article is an introduction to causal properties of General Relativity. Topics include the Raychaudhuri equation, singularity theorems of Penrose and Hawking, the black hole area theorem, topological censorship, and the Gao-Wald theorem. The article is based on lectures at the 2018 summer program Prospects in Theoretical Physics at the Institute for Advanced Study, and also at the 2020 New Zealand Mathematical Research Institute summer school in Nelson, New Zealand. Contents 1 Introduction 3 2 Causal Paths 4 3 Globally Hyperbolic Spacetimes 11 3.1 Definition . 11 3.2 Some Properties of Globally Hyperbolic Spacetimes . 15 3.3 More On Compactness . 18 3.4 Cauchy Horizons . 21 3.5 Causality Conditions . 23 3.6 Maximal Extensions . 24 4 Geodesics and Focal Points 25 4.1 The Riemannian Case . 25 4.2 Lorentz Signature Analog . 28 4.3 Raychaudhuri’s Equation . 31 4.4 Hawking’s Big Bang Singularity Theorem . 35 5 Null Geodesics and Penrose’s Theorem 37 5.1 Promptness . 37 5.2 Promptness And Focal Points . 40 5.3 More On The Boundary Of The Future . 46 1 5.4 The Null Raychaudhuri Equation . 47 5.5 Trapped Surfaces . 52 5.6 Penrose’s Theorem . 54 6 Black Holes 58 6.1 Cosmic Censorship . 58 6.2 The Black Hole Region . 60 6.3 The Horizon And Its Generators . 63 7 Some Additional Topics 66 7.1 Topological Censorship . 67 7.2 The Averaged Null Energy Condition . -
Modified Gravity and Thermodynamics of Time-Dependent Wormholes At
Journal of High Energy Physics, Gravitation and Cosmology, 2017, 3, 708-714 http://www.scirp.org/journal/jhepgc ISSN Online: 2380-4335 ISSN Print: 2380-4327 Modified fR( ) Gravity and Thermodynamics of Time-Dependent Wormholes at Event Horizon Hamidreza Saiedi Department of Physics, Florida Atlantic University, Boca Raton, FL, USA How to cite this paper: Saiedi, H. (2017) Abstract Modified f(R) Gravity and Thermodynam- ics of Time-Dependent Wormholes at In the context of modified fR( ) gravity theory, we study time-dependent Event Horizon. Journal of High Energy wormhole spacetimes in the radiation background. In this framework, we at- Physics, Gravitation and Cosmology, 3, 708-714. tempt to generalize the thermodynamic properties of time-dependent worm- https://doi.org/10.4236/jhepgc.2017.34053 holes in fR( ) gravity. Finally, at event horizon, the rate of change of total Received: August 1, 2017 entropy has been discussed. Accepted: October 20, 2017 Published: October 23, 2017 Keywords Copyright © 2017 by author and fR( ) Gravity, Time-Dependent Wormholes, Thermodynamics, Scientific Research Publishing Inc. Event Horizon This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ 1. Introduction Open Access Wormholes, short cuts between otherwise distant or unconnected regions of the universe, have become a popular research topic since the influential paper of Morris and Thorne [1]. Early work was reviewed in the book of Visser [2]. The Morris-Thorne (MT) study was restricted to static, spherically symmetric space-times, and initially there were various attempts to generalize the definition of wormhole by inserting time-dependent factors into the metric. -
Problem Set 4 (Causal Structure)
\Singularities, Black Holes, Thermodynamics in Relativistic Spacetimes": Problem Set 4 (causal structure) 1. Wald (1984): ch. 8, problems 1{2 2. Prove or give a counter-example: there is a spacetime with two points simultaneously con- nectable by a timelike geodesic, a null geodesic and a spacelike geodesic. 3. Prove or give a counter-example: if two points are causally related, there is a spacelike curve connecting them. 4. Prove or give a counter-example: any two points of a spacetime can be joined by a spacelike curve. (Hint: there are three cases to consider, first that the temporal futures of the two points intesect, second that their temporal pasts do, and third that neither their temporal futures nor their temporal pasts intersect; recall that the manifold must be connected.) 5. Prove or give a counter-example: every flat Lorentzian metric is temporally orientable. 6. Prove or give a counter-example: if the temporal futures of two points do not intersect, then neither do their temporal pasts. 7. Prove or give a counter-example: for a point p in a spacetime, the temporal past of the temporal future of the temporal past of the temporal future. of p is the entire spacetime. (Hint: if two points can be joined by a spacelike curve, then they can be joined by a curve consisting of some finite number of null geodesic segments glued together; recall that the manifold is connected.) 8. Prove or give a counter-example: if the temporal past of p contains the entire temporal future of q, then there is a closed timelike curve through p. -
Theoretical Computer Science Causal Set Topology
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Theoretical Computer Science 405 (2008) 188–197 Contents lists available at ScienceDirect Theoretical Computer Science journal homepage: www.elsevier.com/locate/tcs Causal set topology Sumati Surya Raman Research Institute, Bangalore, India article info a b s t r a c t Keywords: The Causal Set Theory (CST) approach to quantum gravity is motivated by the observation Space–time that, associated with any causal spacetime (M, g) is a poset (M, ≺), with the order relation Causality ≺ corresponding to the spacetime causal relation. Spacetime in CST is assumed to have a Topology Posets fundamental atomicity or discreteness, and is replaced by a locally finite poset, the causal Quantum gravity set. In order to obtain a well defined continuum approximation, the causal set must possess the requisite intrinsic topological and geometric properties that characterise a continuum spacetime in the large. The study of causal set topology is thus dictated by the nature of the continuum approximation. We review the status of causal set topology and present some new results relating poset and spacetime topologies. The hope is that in the process, some of the ideas and questions arising from CST will be made accessible to the larger community of computer scientists and mathematicians working on posets. © 2008 Published by Elsevier B.V. 1. The spacetime poset and causal sets In Einstein’s theory of gravity, space and time are merged into a single entity represented by a pseudo-Riemannian or Lorentzian geometry g of signature − + ++ on a differentiable four dimensional manifold M. -
Isometric Embeddings in Cosmology and Astrophysics
PRAMANA c Indian Academy of Sciences Vol. 77, No. 3 — journal of September 2011 physics pp. 415–428 Isometric embeddings in cosmology and astrophysics GARETH AMERY∗, JOTHI MOODLEY and JAMES PAUL LONDAL Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa ∗Corresponding author. E-mail: [email protected] Abstract. Recent interest in higher-dimensional cosmological models has prompted some signifi- cant work on the mathematical technicalities of how one goes about embedding spacetimes into some higher-dimensional space. We survey results in the literature (existence theorems and simple explicit embeddings); briefly outline our work on global embeddings as well as explicit results for more com- plex geometries; and provide some examples. These results are contextualized physically, so as to provide a foundation for a detailed commentary on several key issues in the field such as: the mean- ing of ‘Ricci equivalent’ embeddings; the uniqueness of local (or global) embeddings; symmetry inheritance properties; and astrophysical constraints. Keywords. Embedding theory; cosmology; astrophysics. PACS Nos 04.20.Jb, 04.20.Ex, 04.50.−h 1. Introduction Extensions to general relativity often involve extra dimensions. Inspired by string theory [1], D-brane theory [2] and Horava–Witten theory [3], there has been a great deal of inter- est in extra-dimensional effective theories, evidenced by phenomenological models such as the Randall–Sundrum [4], Arkani–Hamed–Dimopoulos–Dvali [5] and Dvali–Gabadadze– Porrati [6] scenarios, which attempt to tackle problems such as the mass-hierarchy problem, the origins of the primordial spectrum, the inflationary field and dark energy. -
Quantum Fluctuations and Thermodynamic Processes in The
Quantum fluctuations and thermodynamic processes in the presence of closed timelike curves by Tsunefumi Tanaka A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physics Montana State University © Copyright by Tsunefumi Tanaka (1997) Abstract: A closed timelike curve (CTC) is a closed loop in spacetime whose tangent vector is everywhere timelike. A spacetime which contains CTC’s will allow time travel. One of these spacetimes is Grant space. It can be constructed from Minkowski space by imposing periodic boundary conditions in spatial directions and making the boundaries move toward each other. If Hawking’s chronology protection conjecture is correct, there must be a physical mechanism preventing the formation of CTC’s. Currently the most promising candidate for the chronology protection mechanism is the back reaction of the metric to quantum vacuum fluctuations. In this thesis the quantum fluctuations for a massive scalar field, a self-interacting field, and for a field at nonzero temperature are calculated in Grant space. The stress-energy tensor is found to remain finite everywhere in Grant space for the massive scalar field with sufficiently large field mass. Otherwise it diverges on chronology horizons like the stress-energy tensor for a massless scalar field. If CTC’s exist they will have profound effects on physical processes. Causality can be protected even in the presence of CTC’s if the self-consistency condition is imposed on all processes. Simple classical thermodynamic processes of a box filled with ideal gas in the presence of CTC’s are studied. If a system of boxes is closed, its state does not change as it travels through a region of spacetime with CTC’s. -
On the Categorical and Topological Structure of Timelike Homotopy Classes of Paths in Smooth Spacetimes
ON THE CATEGORICAL AND TOPOLOGICAL STRUCTURE OF TIMELIKE AND CAUSAL HOMOTOPY CLASSES OF PATHS IN SMOOTH SPACETIMES MARTIN GUNTHER¨ ∗ Institute of Algebra and Geometry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. Abstract. For a smooth spacetime X, based on the timelike homotopy classes of its timelike paths, we define a topology on X that refines the Alexandrov topology and always coincides with the manifold topology. The space of timelike or causal homotopy classes forms a semicategory or a category, respectively. We show that either of these algebraic structures encodes enough information to reconstruct the topology and conformal structure of X. Furthermore, the space of timelike homotopy classes carries a natural topology that we prove to be locally euclidean but, in general, not Hausdorff. The presented results do not require any causality conditions on X and do also hold under weaker regularity assumptions. 1. Main results For simplicity, (X; g) will be a smooth spacetime throughout this paper, i.e. a smooth time-oriented Lorentzian manifold. Nevertheless, all of the following results are true for a broader class of manifolds, namely C1-spacetimes that satisfy lemma 2.1, which is a local condition on the topology and chronological structure. Let P (X) be the space of paths in X, i.e. continuous maps [0; 1] ! X, and t c arXiv:2008.00265v2 [math.DG] 13 Aug 2021 P (X) ⊆ P (X) ⊆ P (X) the spaces of continuous future-directed timelike or causal paths in X. A juxtaposed pair of points x; y 2 X shall restrict t=c these sets to only paths from x to y. -
Chapter 2: Minkowski Spacetime
Chapter 2 Minkowski spacetime 2.1 Events An event is some occurrence which takes place at some instant in time at some particular point in space. Your birth was an event. JFK's assassination was an event. Each downbeat of a butterfly’s wingtip is an event. Every collision between air molecules is an event. Snap your fingers right now | that was an event. The set of all possible events is called spacetime. A point particle, or any stable object of negligible size, will follow some trajectory through spacetime which is called the worldline of the object. The set of all spacetime trajectories of the points comprising an extended object will fill some region of spacetime which is called the worldvolume of the object. 2.2 Reference frames w 1 w 2 w 3 w 4 To label points in space, it is convenient to introduce spatial coordinates so that every point is uniquely associ- ated with some triplet of numbers (x1; x2; x3). Similarly, to label events in spacetime, it is convenient to introduce spacetime coordinates so that every event is uniquely t associated with a set of four numbers. The resulting spacetime coordinate system is called a reference frame . Particularly convenient are inertial reference frames, in which coordinates have the form (t; x1; x2; x3) (where the superscripts here are coordinate labels, not powers). The set of events in which x1, x2, and x3 have arbi- x 1 trary fixed (real) values while t ranges from −∞ to +1 represent the worldline of a particle, or hypothetical ob- x 2 server, which is subject to no external forces and is at Figure 2.1: An inertial reference frame.