Metastable massive gravitons from an infinite extra dimension

TL;DR

This paper explores the existence of metastable massive graviton resonances in a braneworld model with an extra dimension, revealing their impact on gravity and cosmological phenomena.

Contribution

It demonstrates the presence of discrete metastable graviton states beyond the zero-mode, providing new insights into gravitational behavior in extra-dimensional models.

Findings

Existence of metastable massive graviton resonances.

Resonances influence corrections to 4D gravity.

Simplified phenomenology of braneworld perturbations.

Abstract

Motivated by stringy considerations, Randall & Sundrum have proposed a model where all the fields and particles of physics, save gravity, are confined on a 4-dimensional brane embedded in 5-dimensional anti-deSitter space. Their scenario features a stable bound state of bulk gravity waves and the brane that reproduces standard general relativity. We demonstrate that in addition to this zero-mode, there is also a discrete set of metastable bound states that behave like massive 4-dimensional gravitons which decay by tunneling into the bulk. These are resonances of the bulk-brane system akin to black hole quasinormal modes--as such, they give rise to the dominant corrections to 4-dimensional gravity. The phenomenology of braneworld perturbations is greatly simplified when these resonant modes are taken into account, which is illustrated by considering gravitational radiation emitted from nearby sources and early universe physics.