Reheating via gravitational particle production in the kination epoch

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 GeV regime.

Phase Transitions in an Expanding Universe: Stochastic Gravitational Waves in Standard and Non-Standard Histories

“…An early matter dominated era, for example, is motivated by the cosmological moduli problem [56][57][58][59], hints from dark matter searches [60][61][62][63][64][65][66][67][68], and perhaps even baryogenesis [69]. Another possibility of a non-standard expansion history is kination, which we do not cover in this paper but can be explored by our methods [70][71][72][73][74][75][76][77][78][79]. We note that gravitational waves have been previously employed to investigate early universe cosmology [80][81][82][83][84][85].…”

Cosmological Particle Production: A Review

“…Some more recent work on the role of gravitational particle creation in various reheating models has been given, for example, in Refs. [52][53][54][55][56][57]. Dissipation and entropy production have been discussed in Refs.…”

Reheating in the kination epoch via multi-channel decay of gravitationally created massive scalars

“…In this case the equation of state takes the form ρ = p corresponding to a universe dominated by stiff matter. While the idea of reheating by particle creation through a sudden or smooth change of the metric has received a lot of attention lately [10][11][12][13][14][15][16][17][18][19], it is by no means the only mechanism capable of reheating: the very expansion itself creates particles making it possible to reheat the Universe using it [20].…”

“…In our previous article [20] we investigated this type of reheating where massive scalars gravitationally created in the stiff-matter era, decayed to massless scalars (radiation) which ultimately reheat the Universe. The standard model, or some other model, particles are eventually produced from these relativistic particles.…”