Higher-Dimensional Minimal Theory of Mass-Varying Massive Gravity And Its Cosmological Consequences

TL;DR

This paper develops a higher-dimensional minimal theory of mass-varying massive gravity with scalar potential coupling to vielbein, analyzing its cosmological implications including critical points and late-time acceleration scenarios.

Contribution

It introduces a novel higher-dimensional minimal theory of mass-varying massive gravity with unique scalar coupling, maintaining the same graviton degrees of freedom as general relativity.

Findings

The theory has eight critical points, five massless and three massive.

It can describe late-time cosmic acceleration via constant graviton mass or dynamic scalar field.

The theory offers new insights into dark energy and late-time cosmology.

Abstract

In this paper we construct higher-dimensional minimal theory of mass-varying massive gravity (MTMVMG) where the masslike scalar potential is coupled to a vielbein potential, unlike in the previous literature where it is coupled to metric, such that the number of graviton degrees of freedom in the theory is the same as in general relativity. We then study the cosmological aspects of this theory and show that it has eight critical points: five in the massless sector and three in the massive sector. In contrast to the standard theory of mass-varying massive gravity where the graviton mass asymptotically approaches zero at late times, hence making the contribution of massive gravity to the late-time cosmic expansion minimum, the MTMVMG can provide good descriptions both in the massless and massive sectors. Especially, there are at least two interesting possible scenarios for the late-time cosmology in the theory: the dark energy is either due to the constant graviton mass which comes from the scalar field that becomes frozen after the reheating era, or due to the quintessence paradigm where the scalar field is dynamic. Therefore, if the accelerating expansion of the universe in the massless sector can be explained by standard quintessence paradigm, in the massive sector it has to be explained by the nontrivial interplay between quintessence and massive gravity.