From massive gravity to modified general relativity II

TL;DR

This paper explores the massless limit of massive gravity, deriving new couplings between scalar matter and gravity, leading to modifications of general relativity at the classical level.

Contribution

It introduces additional couplings between scalar matter and gravity beyond the standard energy-momentum tensor, extending the classical theory of general relativity.

Findings

Derived the most general scalar matter-gravity couplings from gauge invariance.

Identified modifications to general relativity in the massless graviton limit.

Proposed new interactions that alter classical gravitational dynamics.

Abstract

We continue our investigation of massive gravity in the massless limit of vanishing graviton mass. From gauge invariance we derive the most general coupling between scalar matter and gravity. We get further couplings beside the standard coupling to the energy-momentum tensor. On the classical level this leads to a further modification of general relativity.