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

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 $\int dy \sqrt{-G^{(5)}} (T^μ_μ-2T^5_5)=0$ is implemented.

Figures (4)

• Figure 1: $+-+$ model with two $"+"$ branes at the fixed points and moving $"-"$ branes. In the limiting case when $x \rightarrow 0$ we have a RS configuration.
• Figure 2: GRS model can be obtained from the left part of $+--+$ configuration. The whole configuration can be considered as two GRS models connected via flat space.
• Figure 3: Behaviour $\Psi_{m}^2(0)$ in a $+-+$ model (discrete spectrum). For a general $+--+$ model the discrete spectrum density increases with the increase of $x_{-}$ and spectrum becomes continuous in GRS limit.
• Figure 4: A periodic array of positive and negative branes is a model of Crystal Brane Universe kaloper.