Relaxation dominated cosmological expansion

TL;DR

This paper investigates the near-singularity behavior of isotropic, homogeneous cosmological models with viscous fluids, revealing a relaxation dominated regime and potential for relaxation-driven inflation.

Contribution

It introduces the concept of relaxation dominated regimes in cosmology using extended irreversible thermodynamics and compares it with truncated theories, discovering new singular behaviors.

Findings

Identification of a relaxation dominated regime near singularity.

Existence of a relaxation-driven inflationary epoch for fluids with small heat capacity.

Comparison between extended and truncated thermodynamic theories.

Abstract

The behavior near the singularity of an isotropic, homogeneous cosmological model with a viscous fluid source is investigated. This turns out to be a relaxation dominated regime. Full extended irreversible thermodynamics is used, and comparison with results of the truncated theory is made. New singular behaviors are found and it is shown that a relaxation dominated inflationary epoch may exist for fluids with small heat capacity.