Understanding gravitational particle production in quintessential inflation

Abstract

The diagonalization method, introduced by a group of Russian scientists at the beginning of seventies, is used to compute the energy density of superheavy massive particles produced due to a sudden phase transition from inflation to kination in quintessential inflation models, the models unifying inflation with quintessence originally proposed by Peebles-Vilenkin. These superheavy particles must decay in lighter ones to form a relativistic plasma, whose energy density will eventually dominate the one of the inflaton field, in order to have a hot universe after inflation. In the present article we show that, in order that the overproduction of Gravitational Waves (GWs) during this phase transition does not disturb the Big Bang Nucleosynthesis (BBN) success, the decay has to be produced after the end of the kination regime, obtaining a maximum reheating temperature in the TeV regime.

Quintessential inflation from Lorentzian slow roll

“…From the time duration one can calculate the density of particles in the phase space [96][97][98][99][100][101][102][103][104][105]:…”

A Review of Quintessential Inflation

“…where the constant C has to be chosen in order that the β-Bogoliubov coefficient becomes continuous at τ kin because the Equation ( 209) is a first order differential equation, and then one has to demand continuity to the solution. Thus, after some cumbersome calculation [106] one has…”

Quintessential inflation in Palatini f(R) gravity

“…In this section we calculate the value at which the canonically normalized field φ freezes after the period of kination. It is important to mention that, although there exist other reheating mechanisms, such as instant preheating [10,43], curvaton reheating [44][45][46], Ricci reheating [47,48] or considering warm quintessential inflation [9,49,50], in the present work we consider gravitational reheating [51][52][53]. The reason is twofold.…”