The universe dominated by the extended Chaplygin gas

TL;DR

This paper investigates a universe dominated by the extended Chaplygin gas, analyzing its stability through density perturbations and thermodynamics, and confirming its viability as a cosmological model.

Contribution

It introduces the second order extended Chaplygin gas model and demonstrates its stability without phase transitions or critical points.

Findings

Model is stable in relativistic and Newtonian regimes

No phase transition or critical point observed

Thermodynamic analysis confirms stability

Abstract

In this paper, we consider a universe dominated by the extended Chaplygin gas which recently proposed as the last version of Chaplygin gas models. Here, we only consider the second order term which recovers quadratic barotropic fluid equation of state. The density perturbations analyzed in both relativistic and Newtonian regimes and show that the model is stable without any phase transition and critical point. We confirmed stability of the model using thermodynamics point of view.