Disformal quintessence

TL;DR

This paper explores a scalar field coupled to a disformal metric, deriving conditions for causality and stability, and shows it can potentially cause late-time cosmic acceleration, addressing the coincidence problem.

Contribution

It introduces a disformal coupling in scalar field cosmology and demonstrates its viability for triggering cosmic acceleration.

Findings

Disformal coupling can induce late-time acceleration.

Conditions for causality and stability are established.

Potential to alleviate the coincidence problem.

Abstract

A canonic scalar field minimally coupled to a disformal metric generated by the field itself is considered. Causality and stability conditions are derived for such a field. Cosmological effects are studied and it is shown that the disformal modification could viably trigger an acceleration after a scaling matter era, thus possibly alleviating the coincidence problem.