Unified dissipative dark matter model in a non linear Israel-Stewart theory

TL;DR

This paper investigates a unified dissipative dark matter model within the Israel-Stewart framework, demonstrating its potential to emulate the $ ext{Lambda}$CDM model and behave as quintessence dark energy, while ensuring stability and consistency with observational data.

Contribution

It introduces a non-linear extension of the Israel-Stewart theory for dark matter, analyzing its stability and observational viability, which is a novel approach in dissipative dark matter modeling.

Findings

Solutions can emulate $ ext{Lambda}$CDM at some stages

Solutions behave as quintessence dark energy

Solutions are asymptotically stable and perturbation stable

Abstract

In this paper we study the Statefinder and $Om(x)$ diagnoses of an exact solution of a unified dissipative dark matter model in the framework the Israel-Stewart theory and its non linear extension, considering the condition of positive entropy production. The implementation of two diagnoses in the pair of solutions reveal that both solutions can emulate the $\Lambda$CDM model at some stage of the cosmic evolution and behave as quintessence dark energy. The stability of both solutions is discussed from the point of view of the Liapunov's method, showing that they are asymptotic stable. Additionally we show that the solutions are also stable under small perturbations. A simple analysis of the solutions with the use of observational data suggests that the non linear regime could lead to a inconsistencies-free scenario, i.e., in agreement with the bounds obtained from the perturbative analysis for the velocity of bulk viscous perturbations.