Cosmology Beyond Einstein

Adam Ross Solomon

• Publisher: Springer
• Year: 2016
• Print ISBN:
  9783319466200
• eBook ISBN:
  9783319466217
• Topic: Physical Sciences
• Subtopic: Cosmology

This work investigates the theoretical and cosmological implications of modifying Einstein's theory of general relativity. It explores two classes of modifications to gravity: those in which the graviton is given a small mass, and those in which Lorentz invariance is spontaneously broken. It elucidates the nature of cosmological perturbations in theories of massive bimetric gravity, including a potentially deadly instability. Theories of gravity beyond general relativity could explain why the expansion of the Universe is accelerating, obviating the need for a dark energy, and can also affect the evolution of the early Universe. Next, it investigates the nature of spacetime in massive gravity theories that contain two different spacetime metrics. Lastly, the strongest constraints to date are placed on the size of Lorentz-violating effects in the gravity sector during inflation.

 

Table of contents

• Supervisor’s Foreword
• Abstract
• Parts of this thesis have been published in the following journal articles:
• Acknowledgements
• Contents
• 1 Introduction
• 2 Gravity Beyond General Relativity
• Part I A Massive Graviton
• 3 Cosmological Stability of Massive Bigravity
• 4 Linear Structure Growth in Massive Bigravity
• 5 The Geometry of Doubly-Coupled Bigravity
• 6 Cosmological Implications of Doubly-Coupled Massive Bigravity
• 7 Cosmological Implications of Doubly-Coupled Massive Gravity
• Part II Lorentz Violation
• 8 Lorentz Violation During Inflation
• 9 Discussion and Conclusions
• Appendix A Deriving the Bimetric Perturbation Equations
• Appendix B Explicit Solutions for the Modified Gravity Parameters
• Appendix C Transformation Properties of the Doubly-Coupled Bimetric Action
• Appendix D Einstein-Aether Cosmological Perturbation Equations in Real Space
• Appendix Curriculum Vitae