Viscous Chaplygin Gas Models as a Spherical Top-Hat Collapsing Fluids

TL;DR

This paper investigates the nonlinear evolution of viscous Chaplygin gas models during spherical collapse in Einstein and loop quantum cosmology, analyzing their stability and consistency through various physical parameters.

Contribution

It introduces viscous modified and generalized cosmic Chaplygin gas models into spherical collapse analysis within two gravity frameworks, highlighting their supportive role in structure formation.

Findings

Density contrast remains positive, supporting collapse.

Perturbed equation of state parameter stays positive.

Models show consistent behavior in both gravity theories.

Abstract

We study the spherical top-hat collapse in Einstein gravity and loop quantum cosmology by taking the non-linear evolution of viscous modified variable chaplygin gas and viscous generalized cosmic chaplygin gas. We calculate the equation of state parameter, square speed of sound, perturbed equation of state parameter, perturbed square speed of sound, density contrast and divergence of peculiar velocity in perturbed region and discussed their behavior. It is observed that both chaplygin gas models support the spherical collapse in Einstein as well as loop quantum cosmology because density contrast remains positive in both cases and the perturbed equation of state parameter remains positive at the present epoch as well as near future. It is remarked here that these parameters provide the consistence results for both chaplygin gas models in both gravities.