Event-Symmetric Space-Time “The universe is made of stories, not of atoms.” Muriel Rukeyser Philip Gibbs EVENT-SYMMETRIC SPACE-TIME WEBURBIA PUBLICATION Cyberspace First published in 1998 by Weburbia Press 27 Stanley Mead Bradley Stoke Bristol BS32 0EF [email protected] http://www.weburbia.com/press/ This address is supplied for legal reasons only. Please do not send book proposals as Weburbia does not have facilities for large scale publication. © 1998 Philip Gibbs [email protected] A catalogue record for this book is available from the British Library. Distributed by Weburbia Tel 01454 617659 Electronic copies of this book are available on the world wide web at http://www.weburbia.com/press/esst.htm Philip Gibbs’s right to be identified as the author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved, except that permission is given that this booklet may be reproduced by photocopy or electronic duplication by individuals for personal use only, or by libraries and educational establishments for non-profit purposes only. Mass distribution of copies in any form is prohibited except with the written permission of the author. Printed copies are printed and bound in Great Britain by Weburbia. Dedicated to Alice Contents THE STORYTELLER ................................................................................... 11 Between a story and the world ............................................................. 11 Dreams of Rationalism ........................................................................ 14 Light on Light ...................................................................................... 17 Light-Quanta ....................................................................................... 23 The Principle of Least Action .............................................................. 26 Feynman Meets Dirac ......................................................................... 29 Feynman’s Sum Over Stories ............................................................... 30 Second Quantisation ............................................................................ 35 The Storyteller’s Paradigm .................................................................. 36 THE BEAUTY OF THE TIGER ....................................................................... 39 Natural Beauty .................................................................................... 39 Symmetry in Physics ............................................................................ 44 Hidden Symmetry ................................................................................ 45 Conservation Laws .............................................................................. 46 Relativity ............................................................................................. 48 Gauge Symmetry and Economics ......................................................... 51 Supersymmetry .................................................................................... 54 Universal Symmetry............................................................................. 57 Particle Permutations .......................................................................... 58 Event symmetry ................................................................................... 59 IN A GRAIN OF SAND ................................................................................. 61 Discrete Matter ................................................................................... 61 Unification .......................................................................................... 63 Quantum Gravity ................................................................................. 69 Einstein’s Geometrodynamics .............................................................. 69 The Planck Scale ................................................................................. 72 The Best Attempts ................................................................................ 75 Supergravity ........................................................................................ 76 Canonical Quantum Gravity ................................................................ 78 Non-Commutative Geometry................................................................ 79 Black Hole Thermodynamics ............................................................... 80 Is There a Theory of Everything?......................................................... 83 IS SPACE-TIME DISCRETE? ........................................................................ 88 Seeking the ultimate indivisible ........................................................... 88 Lattice Theories ................................................................................... 90 Lattice Quantum Field Theory ............................................................ 93 Lattice Gauge Theories ....................................................................... 95 Fading Motivations ............................................................................. 99 It from Bit ......................................................................................... 100 Cellular Automata ............................................................................ 103 Discreteness in Quantum Gravity ...................................................... 105 Lattice Quantum Gravity................................................................... 107 Pregeometry ..................................................................................... 108 The Metaphysics of Space-Time ........................................................ 110 So is it or isn't it? .............................................................................. 114 WHAT ABOUT CAUSALITY? .................................................................... 115 Causality in the news ........................................................................ 115 Causality in Physics .......................................................................... 116 A Block Universe .............................................................................. 120 The Second Law of Thermodynamics ................................................. 124 Could the Universe be Gold? ............................................................ 127 Anti-thermodynamic light from the future ......................................... 129 A Crystal Ball ................................................................................... 131 Mixing or Meeting ............................................................................ 132 Matter and Anti-matter ..................................................................... 133 Black Holes, White Holes. ................................................................. 134 The Shape of Things to Come ............................................................ 137 Wider Perspectives............................................................................ 138 Occam’s Razor.................................................................................. 139 An Inhomogeneous Universe ............................................................. 142 Is The Big Bang a White Hole? ......................................................... 144 Time Travel....................................................................................... 146 THE SUPERSTRING SUPERMYSTERY ......................................................... 148 Everything or Nothing? ..................................................................... 148 Why String Theory? .......................................................................... 149 All Is String....................................................................................... 154 Duality .............................................................................................. 156 Black Strings..................................................................................... 162 String Symmetry ................................................................................ 163 THE PRINCIPLE OF EVENT SYMMETRY..................................................... 166 The Bucket of Dust ............................................................................ 166 The Universal Lattice ........................................................................ 167 Witten’s Puzzle.................................................................................. 168 Space-Time and Soap Films .............................................................. 170 Permutation City ............................................................................... 172 More Symmetry ................................................................................. 174 Identical Particles ............................................................................. 178 Clifford’s Legacy ............................................................................... 178 Back to Superstrings .......................................................................... 179 Event-Symmetric Physics ................................................................... 180 EVENT-SYMMETRIC STRING THEORY ...................................................... 182 Leap Frog.......................................................................................... 182 Eight Reasons to Believe ................................................................... 183 String Inspired