Book contents
- Frontmatter
- Contents
- Frequently used symbols
- Preface
- 1 Overview
- Part I Relativity
- Part II The Universe after the first second
- Part III Field theory
- Part IV Inflation and the early Universe
- 18 Slow-roll inflation
- 19 Inflation with modified gravity
- 20 Multi-field dynamics
- 21 Reheating and phase transitions
- 22 Thermal equilibrium and the origin of baryon number
- 23 Cold dark matter and dark energy
- 24 Generating field perturbations at horizon exit
- 25 Generating ζ at horizon exit
- 26 Generating ζ after horizon exit
- 27 Generating primordial isocurvature perturbations
- 28 Slow-roll inflation and observation
- 29 Perspective
- Appendix A Spherical functions
- Appendix B Constants and parameters
- Index
21 - Reheating and phase transitions
from Part IV - Inflation and the early Universe
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Frequently used symbols
- Preface
- 1 Overview
- Part I Relativity
- Part II The Universe after the first second
- Part III Field theory
- Part IV Inflation and the early Universe
- 18 Slow-roll inflation
- 19 Inflation with modified gravity
- 20 Multi-field dynamics
- 21 Reheating and phase transitions
- 22 Thermal equilibrium and the origin of baryon number
- 23 Cold dark matter and dark energy
- 24 Generating field perturbations at horizon exit
- 25 Generating ζ at horizon exit
- 26 Generating ζ after horizon exit
- 27 Generating primordial isocurvature perturbations
- 28 Slow-roll inflation and observation
- 29 Perspective
- Appendix A Spherical functions
- Appendix B Constants and parameters
- Index
Summary
In this and the following two chapters, we consider scenarios for the history of the Universe from the end of inflation to neutrino decoupling at T ~ 1 MeV. Einstein gravity is assumed in all cases. A viable scenario must lead to a radiationdominated Universe at T ~ 1MeV, with properties not too different from those described in Section 4.5. In particular, the abundance of relic particles such as gravitinos or moduli should be below observational bounds. As seen in Section 24.7.3, the detection of a cosmic gravitational wave background may in the far future offer powerful discrimination between different scenarios.
This chapter begins with the reheating process, which establishes thermal equilibrium after inflation and initiates the Hot Big Bang. Then we see how the spontaneous breaking of symmetries may lead to the creation of solitons of various kinds, including in particular cosmic strings and other topological defects. Finally, we discuss the possibility of a short burst of late inflation known as thermal inflation.
Reheating
Initial reheating
At the end of inflation, the entire energy density of the Universe remains locked in the scalar fields. Everything else has presumably been diluted away by the inflationary period. We have to free this energy density by converting it into other forms, with the ultimate goal of creating the Hot Big Bang radiation that is certainly present when the run-up to nucleosynthesis begins at T ~ 1 MeV.
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- The Primordial Density PerturbationCosmology, Inflation and the Origin of Structure, pp. 337 - 357Publisher: Cambridge University PressPrint publication year: 2009