Exact Solutions of Einstein's Field Equations
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Exact Solutions of Einstein’s Field Equations Second Edition HANS STEPHANI Friedrich-Schiller-Universit¨at, Jena DIETRICH KRAMER Friedrich-Schiller-Universit¨at, Jena MALCOLM MACCALLUM Queen Mary, University of London CORNELIUS HOENSELAERS Loughborough University EDUARD HERLT Friedrich-Schiller-Universit¨at, Jena published by the press syndicate of the university of cambridge The Pitt Building, Trumpington Street, Cambridge, United Kingdom cambridge university press The Edinburgh Building, Cambridge CB2 2RU, UK 40 West 20th Street, NewYork, NY 10011-4211, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia Ruiz de Alarc´on 13, 28014 Madrid, Spain Dock House, The Waterfront, Cape Town 8001, South Africa http://www.cambridge.org c H. Stephani, D. Kramer, M. A. H. MacCallum, C. Hoenselaers, E. Herlt 2003 This book is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2003 Printed in the United Kingdom at the University Press, Cambridge Typeface Computer Modern 11/13pt System LATEX2ε [tb] A catalogue record for this book is available from the British Library Library of Congress Cataloguing in Publication data Exact solutions of Einstein’s field equations. – 2nd ed. / H. Stephani ... [et al.]. p. cm. – (Cambridge monographs on mathematical physics) Includes bibliographical references and index. ISBN 0-521-46136-7 1. General relativity (Physics) 2. Gravitational waves. 3. Space and time. 4. Einstein field equations – Numerical solutions. I. Stephani, Hans. II. Series. QC173.6 .E96 2003 530.11–dc21 2002071495 ISBN 0 521 46136 7 hardback Contents Preface xix List of tables xxiii Notation xxvii 1 Introduction 1 1.1 What are exact solutions, and why study them? 1 1.2 The development of the subject 3 1.3 The contents and arrangement of this book 4 1.4 Using this book as a catalogue 7 Part I: General methods 9 2 Differential geometry without a metric 9 2.1 Introduction 9 2.2 Differentiable manifolds 10 2.3 Tangent vectors 12 2.4 One-forms 13 2.5 Tensors 15 2.6 Exterior products and p-forms 17 2.7 The exterior derivative 18 2.8 The Lie derivative 21 2.9 The covariant derivative 23 2.10 The curvature tensor 25 2.11 Fibre bundles 27 vii viii Contents 3 Some topics in Riemannian geometry 30 3.1 Introduction 30 3.2 The metric tensor and tetrads 30 3.3 Calculation of curvature from the metric 34 3.4 Bivectors 35 3.5 Decomposition of the curvature tensor 37 3.6 Spinors 40 3.7 Conformal transformations 43 3.8 Discontinuities and junction conditions 45 4 The Petrov classification 48 4.1 The eigenvalue problem 48 4.2 The Petrov types 49 4.3 Principal null directions and determination of the Petrov types 53 5 Classification of the Ricci tensor and the energy-momentum tensor 57 5.1 The algebraic types of the Ricci tensor 57 5.2 The energy-momentum tensor 60 5.3 The energy conditions 63 5.4 The Rainich conditions 64 5.5 Perfect fluids 65 6 Vector fields 68 6.1 Vector fields and their invariant classification 68 6.1.1 Timelike unit vector fields 70 6.1.2 Geodesic null vector fields 70 6.2 Vector fields and the curvature tensor 72 6.2.1 Timelike unit vector fields 72 6.2.2 Null vector fields 74 7 The Newman–Penrose and related formalisms 75 7.1 The spin coefficients and their transformation laws 75 7.2 The Ricci equations 78 7.3 The Bianchi identities 81 7.4 The GHP calculus 84 7.5 Geodesic null congruences 86 7.6 The Goldberg–Sachs theorem and its generalizations 87 Contents ix 8 Continuous groups of transformations; isometry and homothety groups 91 8.1 Lie groups and Lie algebras 91 8.2 Enumeration of distinct group structures 95 8.3 Transformation groups 97 8.4 Groups of motions 98 8.5 Spaces of constant curvature 101 8.6 Orbits of isometry groups 104 8.6.1 Simply-transitive groups 105 8.6.2 Multiply-transitive groups 106 8.7 Homothety groups 110 9Invariants and the characterization of geometries 112 9.1 Scalar invariants and covariants 113 9.2 The Cartan equivalence method for space-times 116 9.3 Calculating the Cartan scalars 120 9.3.1 Determination of the Petrov and Segre types 120 9.3.2 The remaining steps 124 9.4 Extensions and applications of the Cartan method 125 9.5 Limits of families of space-times 126 10 Generation techniques 129 10.1 Introduction 129 10.2 Lie symmetries of Einstein’s equations 129 10.2.1 Point transformations and their generators 129 10.2.2 How to find the Lie point symmetries of a given differential equation 131 10.2.3 How to use Lie point symmetries: similarity reduction 132 10.3 Symmetries more general than Lie symmetries 134 10.3.1 Contact and Lie–B¨acklund symmetries 134 10.3.2 Generalized and potential symmetries 134 10.4 Prolongation 137 10.4.1 Integral manifolds of differential forms 137 10.4.2 Isovectors, similarity solutions and conservation laws 140 10.4.3 Prolongation structures 141 10.5 Solutions of the linearized equations 145 10.6 B¨acklund transformations 146 10.7 Riemann–Hilbert problems 148 10.8 Harmonic maps 148 10.9 Variational B¨acklund transformations 151 10.10 Hirota’s method 152 x Contents 10.11 Generation methods including perfect fluids 152 10.11.1 Methods using the existence of Killing vectors 152 10.11.2 Conformal transformations 155 Part II: Solutions with groups of motions 157 11 Classification of solutions with isometries or homotheties 157 11.1 The possible space-times with isometries 157 11.2 Isotropy and the curvature tensor 159 11.3 The possible space-times with proper homothetic motions 162 11.4 Summary of solutions with homotheties 167 12 Homogeneous space-times 171 12.1 The possible metrics 171 12.2 Homogeneous vacuum and null Einstein-Maxwell space-times 174 12.3 Homogeneous non-null electromagnetic fields 175 12.4 Homogeneous perfect fluid solutions 177 12.5 Other homogeneous solutions 180 12.6 Summary 181 13 Hypersurface-homogeneous space-times 183 13.1 The possible metrics 183 13.1.1 Metrics with a G6 on V3 183 13.1.2 Metrics with a G4 on V3 183 13.1.3 Metrics with a G3 on V3 187 13.2 Formulations of the field equations 188 13.3 Vacuum, Λ-term and Einstein–Maxwell solutions 194 13.3.1 Solutions with multiply-transitive groups 194 13.3.2 Vacuum spaces with a G3 on V3 196 13.3.3 Einstein spaces with a G3 on V3 199 13.3.4 Einstein–Maxwell solutions with a G3 on V3 201 13.4 Perfect fluid solutions homogeneous on T3 204 13.5 Summary of all metrics with Gr on V3 207 14 Spatially-homogeneous perfect fluid cosmologies 210 14.1 Introduction 210 14.2 Robertson–Walker cosmologies 211 14.3 Cosmologies with a G4 on S3 214 14.4 Cosmologies with a G3 on S3 218 Contents xi 15 Groups G3 on non-null orbits V2. Spherical and plane symmetry 226 15.1 Metric, Killing vectors, and Ricci tensor 226 15.2 Some implications of the existence of an isotropy group I1 228 15.3 Spherical and plane symmetry 229 15.4 Vacuum, Einstein–Maxwell and pure radiation fields 230 15.4.1 Timelike orbits 230 15.4.2 Spacelike orbits 231 15.4.3 Generalized Birkhoff theorem 232 15.4.4 Spherically- and plane-symmetric fields 233 15.5 Dust solutions 235 15.6 Perfect fluid solutions with plane, spherical or pseudospherical symmetry 237 15.6.1 Some basic properties 237 15.6.2 Static solutions 238 15.6.3 Solutions without shear and expansion 238 15.6.4 Expanding solutions without shear 239 15.6.5 Solutions with nonvanishing shear 240 15.7 Plane-symmetric perfect fluid solutions 243 15.7.1 Static solutions 243 15.7.2 Non-static solutions 244 16 Spherically-symmetric perfect fluid solutions 247 16.1 Static solutions 247 16.1.1 Field equations and first integrals 247 16.1.2 Solutions 250 16.2 Non-static solutions 251 16.2.1 The basic equations 251 16.2.2 Expanding solutions without shear 253 16.2.3 Solutions with non-vanishing shear 260 17 Groups G2 and G1 on non-null orbits 264 17.1 Groups G2 on non-null orbits 264 17.1.1 Subdivisions of the groups G2 264 17.1.2 Groups G2I on non-null orbits 265 17.1.3 G2II on non-null orbits 267 17.2 Boost-rotation-symmetric space-times 268 17.3 Group G1 on non-null orbits 271 18 Stationary gravitational fields 275 18.1 The projection formalism 275 xii Contents 18.2 The Ricci tensor on Σ3 277 18.3 Conformal transformation of Σ3 and the field equations 278 18.4 Vacuum and Einstein–Maxwell equations for stationary fields 279 18.5 Geodesic eigenrays 281 18.6 Static fields 283 18.6.1 Definitions 283 18.6.2 Vacuum solutions 284 18.6.3 Electrostatic and magnetostatic Einstein–Maxwell fields 284 18.6.4 Perfect fluid solutions 286 18.7 The conformastationary solutions 287 18.7.1 Conformastationary vacuum solutions 287 18.7.2 Conformastationary Einstein–Maxwell fields 288 18.8 Multipole moments 289 19Stationary axisymmetric fields: basic concepts and field equations 292 19.1 The Killing vectors 292 19.2 Orthogonal surfaces 293 19.3 The metric and the projection formalism 296 19.4 The field equations for stationary axisymmetric Einstein– Maxwell fields 298 19.5 Various forms of the field equations for stationary axisym- metric vacuum fields 299 19.6 Field equations for rotating fluids 302 20 Stationary axisymmetric vacuum solutions 304 20.1 Introduction 304 20.2 Static axisymmetric vacuum solutions (Weyl’s class) 304 20.3 The class of solutions U = U(ω) (Papapetrou’s class) 309 20.4 The class of solutions S = S(A) 310 20.5 The Kerr solution and the Tomimatsu–Sato class 311 20.6 Other solutions 313 20.7 Solutions with factor structure 316 21 Non-empty stationary axisymmetric solutions 319 21.1 Einstein–Maxwell fields 319 21.1.1 Electrostatic and magnetostatic solutions