Cosmological evolution driven by polytropic fluids in an inhomogeneous spacetime

TL;DR

This paper explores a generalized Chaplygin gas model with a polytropic equation of state in an inhomogeneous spacetime, deriving analytical cosmological parameters and testing the model against observational data to address dark energy.

Contribution

It introduces a novel inhomogeneous spacetime framework for the GCG model and derives analytical expressions for key cosmological parameters within this setup.

Findings

Analytical expressions for scale factor, Hubble, and deceleration parameters derived.

Model tested against observational data to constrain parameters.

Viability of GCG in inhomogeneous spacetime evaluated.

Abstract

Addressing the late-time accelerated expansion of the universe, known as the "dark energy problem", remains a central challenge in cosmology. While the cosmological constant is the standard explanation, alternative models such as quintessence, phantom fluids, and Chaplygin gas have been proposed. This work investigates the generalized Chaplygin gas (GCG) model, which is characterized by a polytropic equation of state. We explore this model within the framework of an anisotropic fluid, by means of a metric that reduces to the standard form of the Friedmann-Lema\^itre-Robertson-Walker (FLRW) spacetime at cosmological scales. To assess the model's viability, we derive analytical expressions for the scale factor, the Hubble parameter, and the deceleration parameter. Finally, the model is tested against observational data to constrain its parameters and evaluate its consistency.