Braneworlds, Conformal Fields and the Gravitons

TL;DR

This paper explores the dynamics of Randall-Sundrum braneworlds with conformal matter, analyzing graviton fluctuations and their implications for gravity localization and experimental bounds.

Contribution

It introduces a class of stable 5D warped geometries with conformal fields of weight -4 and studies graviton mode spectra in these backgrounds.

Findings

Stable warped geometries with conformal fields are identified.

Gravity localization is insufficient for large mass hierarchies.

Experimental bounds constrain the model parameters.

Abstract

We investigate the dynamics of Randall-Sundrum AdS5 braneworlds with 5-dimensional conformal matter fields. In the scenario with a compact fifth dimension the class of conformal fields with weight -4 is associated with exact 5-dimensional warped geometries which are stable under radion field perturbations and describe on the brane the dynamics of inhomogeneous dust, generalized dark radiation and homogeneous polytropic dark energy. We analyse the graviton mode flutuations around this class of background solutions and determine their mass eigenvalues and wavefunctions from a Sturm-Liouville problem. We show that the localization of gravity is not sharp enough for large mass hierarchies to be generated. We also discuss the physical bounds imposed by experiments in particle physics, in astrophysics and in precise measurements of the low energy gravitational interaction.