Gauss-Bonnet Chameleon Mechanism of Dark Energy

TL;DR

This paper proposes a modified scalar-Einstein-Gauss-Bonnet gravity model with a Chameleon mechanism to explain dark energy and inflation, while avoiding large corrections to Newton's law by making the scalar mode massive.

Contribution

It introduces an extension of the Chameleon mechanism within scalar-Gauss-Bonnet gravity to suppress deviations from Newtonian gravity and unify early and late universe acceleration.

Findings

Scalar mode becomes massive due to Gauss-Bonnet coupling.

Model can describe both inflation and current acceleration.

Correction to Newton law can be minimized in the Solar System.

Abstract

As a model of the current accelerated expansion of the universe, we consider a model of the scalar-Einstein-Gauss-Bonnet gravity. This model includes the propagating scalar modes, which might give a large correction to the Newton law. In order to avoid this problem, we propose an extension of the Chameleon mechanism where the scalar mode becomes massive due to the coupling with the Gauss-Bonnet term. Since the Gauss-Bonnet invariant does not vanish near the earth or in the Solar System, even in the vacuum, the scalar mode is massive even in the vacuum and the correction to the Newton law could be small. We also discuss about the possibility that the model could describe simultaneously the inflation in the early universe, in addition to the current accelerated expansion.