An extended analysis for a generalized Chaplygin gas model

TL;DR

This paper extends the generalized Chaplygin gas model to include a scalar field description, analyzing its implications for cosmological perturbations, growth of matter perturbations, and thermodynamic laws.

Contribution

It introduces a scalar field formulation for the NGCG model and explores its cosmological and thermodynamic properties.

Findings

Scalar field description exists for the NGCG model

Derived spectral indices for perturbations in the NGCG scenario

Confirmed the viability of the generalized second law of thermodynamics

Abstract

In this work, we have extended the analysis on the generalized Chaplygin gas (GCG) model as the unification of dark energy and dark matter. Specifically, we have shown that the model of our consideration known as the new generalized Chaplygin gas (NGCG) model, admits a scalar field description, which means that there exist a minimally coupled scalar field for a given scalar field potential where the equation of state is that of the NGCG. With the use of the later property we can construct the slow-roll parameters and derive the corresponding values for the spectral indices for the tensor to scalar perturbation and for the density perturbations. We have also studied the growth rate of matter perturbations in the NGCG scenario. Finally, we have studied the viability of the generalized second law of thermodynamics by assuming that the dynamical apparent horizon in a NGCG universe is endowed with Hawking temperature and Bekenstein entropy.