Post-Newtonian Hydrodynamics Post-Newtonian Hydrodynamics : Theory and Applications By Gilberto Medeiros Kremer Post-Newtonian Hydrodynamics: Theory and Applications By Gilberto Medeiros Kremer Departamento de Física Universidade Federal do Paraná Curitiba, Brazil E-mail: [email protected] This book first published 2022 Cambridge Scholars Publishing Lady Stephenson Library, Newcastle upon Tyne, NE6 2PA, UK British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Copyright © 2022 by Gilberto Medeiros Kremer All rights for this book reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owner. ISBN (10): 1-5275-7969-7 ISBN (13): 978-1-5275-7969-9 To Maria Rachel Contents PREFACE xiii 1 THE BOLTZMANN EQUATION: AN OVERVIEW 1 1.1 Non-relativistic Boltzmann equation . . . . . . . 2 1.2 Boltzmann equation in special relativity . . . . . 7 1.3 Boltzmann equation in gravitational fields . . . . . . . . . . . . . . . . . 14 2 FIRST POST-NEWTONIAN APPROXIMATION 27 2.1 Preliminaries . . . . . . . . . . . . . . . . . . . . 28 2.2 The first post-Newtonian approximation . . . . . 31 2.3 The solution of Einstein’s field equations . . . . . . . . . . . . . . . . . . . . . . 37 2.3.1 The Weinberg method . . . . . . . . . . . 37 2.3.2 Explicit expressions for the components . 42 vii 2.3.3 The Chandrasekhar method . . . . . . . . 47 2.4 Hydrodynamic equations for an Eulerian fluid . . . . . . . . . . . . . . . . . . . . 52 2.5 Brans-Dicke post-Newtonian approximation . . . . . . . . . . . . . . . . . . . 58 2.5.1 Brans-Dicke theory . . . . . . . . . . . . . 58 2.5.2 Post-Newtonian Brans-Dicke theory . . . 66 2.5.3 Hydrodynamic equations for an Eulerian fluid . . . . . . . . . . . . . . . 75 2.6 Non-perfect fluid hydrodynamic equations . . . . . . . . . . . . . . . . . . . . . . 78 2.7 The gravitational potentials . . . . . . . . . . . . 86 2.8 The conservation laws . . . . . . . . . . . . . . . 92 2.9 The post-Newtonian virial theorem . . . . . . . . . . . . . . . . . . . . . . . 104 3 SECOND POST-NEWTONIAN APPROXIMA- TION 111 3.1 Preliminaries . . . . . . . . . . . . . . . . . . . . 112 3.2 Equation for determination Ψ . . . . . . . . . . 115 ij 3.3 Equation for determination Ψ . . . . . . . . . . 120 0i 3.4 Equation for determination Ψ . . . . . . . . . . 122 00 3.5 A gauge choice . . . . . . . . . . . . . . . . . . . 124 3.6 Hydrodynamic equations for an Eulerian fluid . . . . . . . . . . . . . . . . . . . . 125 3.7 Conservation laws in general relativity . . . . . . 138 3.7.1 Energy-momentum pseudo-tensor of the gravitational field . . . . . . . . . . . . . . 140 viii 3.7.2 The total linear momentum density con- servation . . . . . . . . . . . . . . . . . . 145 3.7.3 The total energy density conservation . . 148 4 POST-NEWTONIAN KINETIC THEORY 163 4.1 First post-Newtonian approximation . . . . . . . 164 4.1.1 Post-Newtonian Boltzmann equation . . . 164 4.1.2 Post-Newtonian Maxwell-Ju¨ttner distribution function . . . . . . . . . . . . 167 4.1.3 Post-Newtonian macroscopic fields . . . . 169 4.1.4 Post-Newtonian transfer and Eulerian hydrodynamic equations . . . . . . . . . 173 4.2 Second post-Newtonian approximation . . . . . . . . . . . . . . . . . . . 176 4.2.1 Post-Newtonian Boltzmann equation . . . 177 4.2.2 Post-Newtonian Maxwell-Ju¨ttner distribution function . . . . . . . . . . . . 179 4.2.3 Post-Newtonian macroscopic fields . . . . 181 4.2.4 Post-Newtonian hydrodynamic equations . . . . . . . . . . . . . . . . . . 185 4.3 Post-Newtonian Jeans equations . . . . . . . . . 190 4.3.1 Stationary and spherically symmetrical self-gravitating systems . . . . . . . . . . 191 4.3.2 Stationary and axisymmetrical self-gravitating systems . . . . . . . . . . 194 5 STELLAR STRUCTURE MODELS 203 5.1 The polytropic equation of state . . . . . . . . . 204 5.2 Stellar mean molecular weight . . . . . . . . . . . 207 ix