Density perturbations in an Universe dominated by the Chaplygin gas

TL;DR

This paper investigates how density perturbations evolve in a universe dominated by the Chaplygin gas, demonstrating that observed large-scale structures can be explained by tuning the gas's equation of state parameter.

Contribution

It shows that the Chaplygin gas can account for observed density contrasts by adjusting its equation of state, highlighting its potential as a dark energy candidate.

Findings

Density contrast matches observations with parameter tuning.

Negative pressure effects are significant only recently.

Chaplygin gas can explain large-scale structure formation.

Abstract

We study the fate of density perturbations in an Universe dominate by the Chaplygin gas, which exhibit negative pressure. We show that it is possible to obtain the value for the density contrast observed in large scale structure of the Universe by fixing a free parameter in the equation of state of this gas. The negative character of pressure must be significant only very recently.