Modified brane cosmologies with induced gravity, arbitrary matter content and a Gauss-Bonnet term in the bulk

TL;DR

This paper extends brane cosmology models by incorporating a Gauss-Bonnet term and arbitrary matter, analyzing their effects on cosmic evolution, including acceleration and dark radiation effects.

Contribution

It introduces a covariant framework for brane cosmology with Gauss-Bonnet correction and arbitrary matter, detailing bulk matter effects and mirage phenomena.

Findings

Bulk matter influences brane evolution via generalized dark radiation.

The model describes both normal and self-accelerating cosmological branches.

Derived Raychaudhuri equation helps determine conditions for cosmic acceleration.

Abstract

We extend the covariant analysis of the brane cosmological evolution in order to take into account, apart from a general matter content and an induced-gravity term on the brane, a Gauss-Bonnet term in the bulk. The gravitational effect of the bulk matter on the brane evolution can be described in terms of the total bulk mass as measured by a bulk observer at the location of the brane. This mass appears in the effective Friedmann equation through a term characterized as generalized dark radiation that induces mirage effects in the evolution. We discuss the normal and self-accelerating branches of the combined system. We also derive the Raychaudhuri equation that can be used in order to determine if the cosmological evolution is accelerating.