Fluctuating brane in a dilatonic bulk

TL;DR

This paper explores the dynamics of a cosmological brane in a five-dimensional bulk with a scalar field, analyzing both background evolution and brane fluctuations through wave equations for different cosmological scenarios.

Contribution

It introduces a detailed analysis of brane fluctuations in a dilatonic bulk, including wave equations for bouncing and expanding branes, extending previous models of brane cosmology.

Findings

Fluctuation modes obey a wave equation influenced by bulk scalar fields.

Different cosmological behaviors, such as bouncing and expanding, are characterized.

The study provides insights into brane stability and fluctuation dynamics in scalar field backgrounds.

Abstract

We consider a cosmological brane moving in a static five-dimensional bulk spacetime endowed with a scalar field whose potential is exponential. After studying various cosmological behaviours for the homogeneous background, we investigate the fluctuations of the brane that leave spacetime unaffected. A single mode embodies these fluctuations and obeys a wave equation which we study for bouncing and ever-expanding branes.