Brane Universe and Multigravity: Modification of gravity at large and small distances

TL;DR

This paper explores modifications to gravity at large and small distances within a brane universe framework, connecting bi-gravity and GRS models, and discusses stabilization mechanisms for negative tension branes to ensure consistency with General Relativity.

Contribution

It introduces a general model interpolating between bi-gravity and GRS models and proposes a stabilization mechanism for negative tension branes in AdS backgrounds.

Findings

Extra degrees of freedom of massive gravitons can be consistent with GR if stabilization conditions are met.

The model links large-distance gravity modifications to brane tensions and tunneling factors.

Stabilization conditions prevent conflicts with established gravitational theory.

Abstract

We consider a modification of gravity at large distances in a Brane Universe which was discussed recently. In these models the modification of gravity at large distances is ultimately connected to existence of negative tension brane(s) and exponentially small tunneling factor. We discuss a general model which interpolates between Bi-gravity model and GRS model. We also discuss the possible mechanism of stabilization for negative tension branes in AdS background. Finally we show that extra degrees of freedom of massive gravitons do not lead to disastrous contradiction with General Relativity if the stabilization condition $\int dy \sqrt{-G^{(5)}} (T^\mu_\mu-2T^5_5)=0$ is implemented.