Braneworld dynamics in Einstein-Gauss-Bonnet gravity

TL;DR

This paper explores the cosmological evolution of braneworld models in five-dimensional Einstein-Gauss-Bonnet gravity, revealing possibilities for accelerated expansion, phantom-like behavior, and singularity avoidance depending on the nature of the extra dimension.

Contribution

It provides a comprehensive analysis of braneworld cosmology in Einstein-Gauss-Bonnet gravity, including effects of space-like and time-like extra dimensions on cosmic evolution.

Findings

Accelerated expansion at late times, including phantom-like behavior.

Late-time approach to de Sitter space avoiding big-rip singularities.

Bounce solutions in time-like extra dimension models avoiding initial singularity.

Abstract

We discuss the cosmological evolution of a braneworld in five dimensional Gauss-Bonnet gravity. Our discussion allows the fifth (bulk) dimension to be space-like as well as time-like. The resulting equations of motion have the form of a cubic equation in the (H^2,(\rho+\sigma)^2) plane, where \sigma is the brane tension and \rho is the matter density. This allows us to conduct a comprehensive pictorial analysis of cosmological evolution for the Gauss-Bonnet brane. The many interesting properties of this braneworld include the possibility of accelerated expansion at late times. For a finite region in parameter space the accelerated expansion can be phantom-like so that w < -1. At late times, this branch approaches de Sitter space (w = -1) and avoids the big-rip singularities usually present in phantom models. For a time-like extra dimension the Gauss-Bonnet brane can bounce and avoid the initial singularity.