NarIikar J.V., Padmanabhan T. Gravity, Gauge Theories and Quantum Cosmology

Springer; 1986. — 476 p. — (Fundamental Theories of Physics 11). — ISBN-13 978-9027719485.For several decades since its inception, Einstein's general theory of relativity stood somewhat aloof from the rest of physics. Paradoxically, the attributes which normally boost a physical theory - namely, its perfection as a theoreti­ cal framework and the extraordinary intellectual achievement underlying i- prevented the general theory from being assimilated in the mainstream of physics. It was as if theoreticians hesitated to tamper with something that is manifestly so beautiful. Happily, two developments in the 1970s have narrowed the gap. In 1974 Stephen Hawking arrived at the remarkable result that black holes radiate after all. And in the second half of the decade, particle physicists discovered that the only scenario for applying their grand unified theories was offered by the very early phase in the history of the Big Bang universe. In both cases, it was necessary to discuss the ideas of quantum field theory in the background of curved spacetime that is basic to general relativity. This is, however, only half the total story. If gravity is to be brought into the general fold of theoretical physics we have to know how to quantize it. To date this has proved a formidable task although most physicists would agree that, as in the case of grand unified theories, quantum gravity will have applications to cosmology, in the very early stages of the Big Bang universe. In fact, the present picture of the Big Bang universe necessarily forces us to think of quantum cosmology.
In this book we have highlighted these interdisciplinary problems, ending with a simplified version of quantum gravity that appears to provide useful inputs into the problems of the early universe. In particular, the difficulties associated with the classical models that have recently gained prominence under the heads of 'singularity', 'particle horizon' and 'flatness' are resolved in this picture of the quantum universe.
But this is a beginning, not the end of the quest for a general theory of quantum gravity. Indeed, none of the topics discussed in the various parts of this book is free from problems yet to be resolved: thus giving a lie to the belief shared in some circles that the end of physics is almost at hand.Preface
Introduction
PART I QUANTUM THEORY
Path Integrals
En Route to Quantum Field Theory
Quantum Field Theory
Gauge Fields
PART II CLASSICAL GENERAL RELATIVITY
General Theory of Relativity
Gravitating Massive Objects
Relativistic Cosmology
PART III QUANTIZATION IN CURVED SPACETIME
Quantum Theory in Curved Spacetime
The Very Early Universe
PART IV QUANTUM COSMOLOGY
Approaches to Quantum Cosmology
Quantum Conformal Fluctuations
Towards a More Complete Theory
PART V APPENDICES
Appendix A Renormalization
Appendix B Basic Group Theory
Appendix C Differential Geometry
Appendix D Spacetime Symmetries