Lorentz violation in brane cosmology, accelerated expansion and fundamental constants

TL;DR

This paper explores how Lorentz violation in a 5D brane-world model affects cosmological evolution, leading to potential variations in fundamental constants and different expansion behaviors depending on bulk cosmological constant scenarios.

Contribution

It extends Lorentz violation concepts to a 5D brane-world framework with a bulk vector field, analyzing its impact on cosmological parameters and evolution.

Findings

Variation in gravitational constant G over time.

Dependence of expansion behavior on bulk cosmological constant.

Modified Friedmann and Raychaudhuri equations in the model.

Abstract

The notion of Lorentz violation in four dimensions is extended to a 5-dimensional brane-world scenario by utilizing a dynamical vector field assumed to point in the bulk direction, with Lorentz invariance holding on the brane. The cosmological consequences of this theory consisting of the time variation in the gravitational coupling $G$ and cosmological term $\Lambda_4$ are explored. The brane evolution is addressed by studying the generalized Friedmann and Raychaudhuri equations. The behavior of the expansion scale factor is then considered for different possible scenarios where the bulk cosmological constant is zero, positive or negative.