Brane World Cosmologies with Varying Speed of Light

TL;DR

This paper explores brane world cosmologies within Randall-Sundrum models, examining how a time-varying speed of light can address fundamental cosmological problems and the constraints imposed by extra-dimensional physics.

Contribution

It analyzes the feasibility of VSL cosmologies in RS models, highlighting the restrictive conditions and potential mechanisms for controlling quantum corrections post-SUSY breaking.

Findings

VSL can potentially solve flatness and cosmological constant problems in RS models.

RS models impose stricter conditions on VSL cosmologies than standard GR.

VSL mechanisms may help regulate quantum corrections after SUSY breaking.

Abstract

We study cosmologies in the Randall-Sundrum models, incorporating the possibility of time-varying speed of light and Newton's constant. The cosmologies with varying speed of light (VSL) were proposed by Moffat and by Albrecht and Magueijo as an alternative to inflation for solving the cosmological problems. We consider the case in which the speed of light varies with time after the radion or the scale of the extra dimension has been stabilized. We elaborate on the conditions under which the flatness problem and the cosmological constant problem can be resolved. We find that the RS models are more restrictive about possible desirable VSL cosmological models than the standard general relativity. Particularly, the VSL cosmologies may provide with a possible mechanism for bringing the quantum corrections to the fine-tuned brane tensions after the SUSY breaking under control.