Scalar models for the unification of the dark sector

TL;DR

This paper reviews the challenges faced by the generalized Chaplygin gas model in fitting observational data and proposes a scalar field approach within Rastall's gravity to address these issues.

Contribution

It introduces a scalar field representation with non-canonical form in Rastall's gravity as a novel way to unify the dark sector.

Findings

Scalar field model can potentially resolve observational tensions

Non-canonical scalar fields are necessary for success

Rastall's gravity provides a suitable framework

Abstract

We review the difficulties of the generalized Chaplygin gas model to fit observational data, due to the tension between background and perturbative tests. We argue that such issues may be circumvented by means of a self-interacting scalar field representation of the model. However, this proposal seems to be successful only if the self-interacting scalar field has a non-canonical form. The latter can be implemented in Rastall's theory of gravity.