Cosmology Beyond Einstein

1. Front Matter

   Pages i-xxi

   PDF

2. Introduction

   • Adam Ross Solomon

   Pages 1-20

3. Gravity Beyond General Relativity

   • Adam Ross Solomon

   Pages 21-51

4. A Massive Graviton

   1. Front Matter

      Pages 53-53

      PDF

   2. Cosmological Stability of Massive Bigravity

      • Adam Ross Solomon

      Pages 55-70

   3. Linear Structure Growth in Massive Bigravity

      • Adam Ross Solomon

      Pages 71-101

   4. The Geometry of Doubly-Coupled Bigravity

      • Adam Ross Solomon

      Pages 103-115

   5. Cosmological Implications of Doubly-Coupled Massive Bigravity

      • Adam Ross Solomon

      Pages 117-134

   6. Cosmological Implications of Doubly-Coupled Massive Gravity

      • Adam Ross Solomon

      Pages 135-151

5. Lorentz Violation

   1. Front Matter

      Pages 153-153

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   2. Lorentz Violation During Inflation

      • Adam Ross Solomon

      Pages 155-195

   3. Discussion and Conclusions

      • Adam Ross Solomon

      Pages 197-206

6. Back Matter

   Pages 207-231

   PDF

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.
 

• Massive Gravity
• Bimetric Gravity
• Massive Bigravity
• Modified Gravity
• Einstein-Aether Theory
• Lorentz Violation
• Cosmological Perturbation Theory
• Dark Energy
• Cosmological Inflation
• Theoretical Cosmology

• Center for Particle Cosmology, University of Pennsylvania, Philadelphia, USA

  Adam Ross Solomon

Adam Solomon is a theoretical cosmologist interested in how we can unveil the fundamental laws of physics by looking to the sky. While his research has spanned a variety of cosmological observations and fundamental theories, he has focused especially on the mystery of the accelerating expansion of the Universe, and whether this may be a sign of new gravitational physics beyond Einstein's general relativity.


He is currently a postdoctoral fellow at the Center for Particle Cosmology at the University of Pennsylvania, having obtained his bachelors at Yale University and his doctorate at the University of Cambridge.

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