Gravitational particle production of superheavy massive particles in Quintessential Inflation: A numerical analysis

TL;DR

This paper numerically analyzes gravitational production of superheavy particles during Quintessential Inflation, showing they can lead to high reheating temperatures without disrupting Big Bang Nucleosynthesis.

Contribution

It provides a detailed numerical study of particle production and reheating in two Quintessential Inflation models, highlighting the potential for high reheating temperatures.

Findings

Reheating temperatures exceed 10^7 GeV in both models.

Superheavy particles are efficiently produced despite their large mass.

Gravitational wave overproduction does not affect BBN success.

Abstract

We compute numerically the reheating temperature due to the gravitational production of conformally coupled superheavy particles during the phase transition from the end of inflation to the beginning of kination in two different Quintessential Inflation (QI) scenarios, namely Lorentzian Quintessential Inflation (LQI) and $\alpha$-attractors in the context of Quintessential Inflation ($\alpha$-QI). Once these superheavy particles have been created, they must decay into lighter ones to form a relativistic plasma, whose energy density will eventually dominate the one of the inflaton field in order to reheat after inflation our universe with a very high temperature, in both cases greater than $10^7$ GeV, contrary to the usual belief that heavy masses suppress the particle production and, thus, lead to an inefficient reheating temperature. Finally, we will show that the over-production of Gravitational Waves (GWs) during this phase transition, when one deals with our models, does not disturb the Big Bang Nucleosynthesis (BBN) success.