5-Dimensional Warped Cosmological Solutions With Radius Stabilization by a Bulk Scalar

TL;DR

This paper derives 5D cosmological solutions within the Randall-Sundrum model, incorporating the Goldberger-Wise stabilization mechanism, and examines how matter and cosmological expansion influence the extra dimension and physical mass scales.

Contribution

It provides a detailed, gauge-invariant analysis of perturbations in stabilized 5D warped cosmology, confirming previous estimates of radius shifts and exploring their cosmological implications.

Findings

Perturbations in the bulk scalar can be gauged away.

The radius of the extra dimension shifts due to matter are confirmed.

Mass scales on the TeV brane can change significantly over cosmological time.

Abstract

We present the 5-dimensional cosmological solutions in the Randall-Sundrum warped compactification scenario, using the Goldberger-Wise mechanism to stabilize the size of the extra dimension. Matter on the Planck and TeV branes is treated perturbatively, to first order. The back-reaction of the scalar field on the metric is taken into account. We identify the appropriate gauge-invariant degrees of freedom, and show that the perturbations in the bulk scalar can be gauged away. We confirm previous, less exact computations of the shift in the radius of the extra dimension induced by matter. We point out that the physical mass scales on the TeV brane may have changed significantly since the electroweak epoch due to cosmological expansion, independently of the details of radius stabilization.