On the stability of gravity in the presence of a non-minimally coupled scalar field

TL;DR

This paper demonstrates the stability of Einstein's gravity with a non-minimally coupled scalar field under certain conditions, explores inflationary solutions, and proposes a new reheating mechanism.

Contribution

It reveals stability conditions for gravity with non-minimal scalar coupling and introduces a novel reheating mechanism in inflationary models.

Findings

Gravity remains stable at high scalar field values with reversed Einstein-Hilbert sign.

Identification of inflationary solutions within this framework.

Proposal of a new reheating mechanism during inflation.

Abstract

We show that Einstein's gravity coupled to a non-minimally coupled scalar field is stable even for high values of the scalar field, when the sign of the Einstein-Hilbert action is reversed. We also discuss inflationary solutions and a possible new mechanism of reheating.