Locally Localized Gravity

TL;DR

This paper investigates gravity fluctuations around non-fine-tuned branes, demonstrating that a massive bound state graviton can reproduce four-dimensional gravity in an AdS4/AdS5 setup with small cosmological constant.

Contribution

It shows that a massive bound state graviton can mimic four-dimensional gravity on a non-fine-tuned brane in AdS space, extending previous models.

Findings

Existence of a bound state graviton for small cosmological constant

Four-dimensional gravity is recovered despite the infinite volume of the space

The bound state graviton is massive, not massless

Abstract

We study the fluctuation spectrum of linearized gravity around non-fine-tuned branes. We focus on the case of an AdS4 brane in AdS5. In this case, for small cosmological constant, the warp factor near the brane is essentially that of a Minkowski brane. However, far from the brane, the metric differs substantially. The space includes the AdS5 boundary, so it has infinite volume. Nonetheless, for sufficiently small AdS4 cosmological constant, there is a bound state graviton in the theory, and four-dimensional gravity is reproduced. However, it is a massive bound state that plays the role of the four-dimensional graviton.