Relations between the modified Chaplygin gas and a scalar field

TL;DR

This paper explores the relationship between the modified Chaplygin gas and scalar fields in cosmology, providing new analytical solutions and highlighting potential features like multiple minima in the scalar potential.

Contribution

It introduces more general analytical solutions relating the modified Chaplygin gas to scalar fields, including cases with curvature, and discusses implications for cosmological perturbations.

Findings

New analytical solutions for curvature-free case

Identification of potential for two minima in scalar field

Analytical result for density contrast in perturbations

Abstract

In this work the modified Chaplygin gas is related to a cosmological scalar field. Analytical results, more general than the solutions previously shown in the literature, are presented for the case when the curvature is absent, and one entirely new particular result is shown for a case where there is curvature. Also, it is emphasized here that one interesting feature of the scalar field associated to the modified Chaplygin gas is the possible presence of two minima in its potential. Finally, it is argued that the scalar field representation of the Chaplygin gas can be another useful tool in the study of the evolution of perturbations and, as an example of this, a new analytical result for the density contrast is presented.