Chaplygin gas and the cosmological evolution of alpha

TL;DR

This paper explores how Chaplygin gas models, as dark energy candidates, can cause variations in the fine structure constant over cosmic time, and compares these predictions with observational data.

Contribution

It reconstructs Chaplygin gas models as scalar fields and tests their consistency with observational constraints on alpha variation.

Findings

Chaplygin gas models can accommodate observed alpha variations.

Models are consistent with current observational constraints.

The equivalence principle remains respected in these models.

Abstract

The class of Chaplygin gas models regarded as a candidate of dark energy can be realized by a scalar field, which could drive the variation of the fine structure constant $\alpha$ during the cosmic time. This phenomenon has been observed for almost ten years ago from the quasar absorption spectra and attracted many attentions. In this paper, we reconstruct the class of Chaplygin gas models to a kind of scalar fields and confront the resulting $\Delta\alpha/\alpha$ with the observational constraints. We found that if the present observational value of the equation of state of the dark energy was not exactly equal to -1, various parameters of the class of Chaplygin gas models are allowed to satisfy the observational constraints, as well as the equivalence principle is also respected.