Cosmological Perturbations in Brane Worlds: Brane Bending and Anisotropic Stresses

TL;DR

This paper develops a metric-based formalism to analyze cosmological perturbations in brane world models, focusing on the relationship between brane bending and anisotropic stresses, and introduces a gauge for unified treatment of perturbations.

Contribution

It presents a unique gauge choice for treating perturbations in brane worlds, linking anisotropic stress and brane bending within a comprehensive formalism.

Findings

Established a gauge where brane and bulk perturbations are treated generally.

Connected anisotropic stress on the brane to brane bending effects.

Commented on gravitational interactions between branes and the bulk.

Abstract

Using a metric-based formalism to treat cosmological perturbations, we discuss the connection between anisotropic stress on the brane and brane bending. First we discuss gauge-transformations, and draw our attention to gauges, in which the brane-positions remain unperturbed. We provide a unique gauge, where perturbations both on the brane and in the bulk can be treated with generality. For vanishing anisotropic stresses on the brane, this gauge reduces to the generalized longitudinal gauge. We further comment on the gravitational interaction between the branes and the bulk.