Reheating via gravitational particle production in kination epoch

TL;DR

This paper investigates gravitational particle production during the kination epoch, providing detailed numerical analysis of reheating temperatures and the transition to radiation domination in the early universe.

Contribution

It offers a precise, quantum field theory-based analysis of reheating via gravitational particle production in the kination regime, including decay processes and temperature estimates.

Findings

Reheating temperature ranges from 10^6 to 10^12 GeV.

Universe temporarily dominated by matter before radiation era.

Numerical solutions of Boltzmann equations confirm the reheating process.

Abstract

We provide a detailed study of reheating in the kination regime where particle content is created by gravitational production of massive scalars mutually interacting with a massless scalar field. The produced particles subsequently decay into massless particles eventually reheating the Universe. We aim for a more precise picture using Boltzmann equations and decay rates obtained by methods of quantum field theory in curved spacetime. By numerical calculations it is found that after inflation the Universe ends up being dominated by ordinary matter for a while before the radiation dominated era. The reheating temperature itself is found to be in the $10^6-10^{12}\ \text{GeV}$ regime.