Extending the generalized Chaplygin gas model by using geometrothermodynamics

TL;DR

This paper employs geometrothermodynamics to derive fundamental equations for cosmological models, extending the generalized Chaplygin gas model to include thermodynamic interactions that describe the dark sector of the Universe.

Contribution

It introduces a novel approach using geometrothermodynamics to extend the generalized Chaplygin gas model in cosmology.

Findings

The simplest fundamental equation models standard cosmological fluids.

A new fundamental equation with thermodynamic interaction describes dark energy and dark matter.

The extended model encompasses the generalized Chaplygin gas as a special case.

Abstract

We use the formalism of geometrothermodynamics (GTD) to derive fundamental thermodynamic equations that are used to construct general relativistic cosmological models. In particular, we show that the simplest possible fundamental equation, which corresponds in GTD to a system with no internal thermodynamic interaction, describes the different fluids of the standard model of cosmology. In addition, a particular fundamental equation with internal thermodynamic interaction is shown to generate a new cosmological model that correctly describes the dark sector of the Universe and contains as a special case the generalized Chaplygin gas model.