String inspired braneworld cosmology

TL;DR

This paper explores braneworld cosmology models inspired by string theory, incorporating Gauss-Bonnet corrections, revealing dynamic gravitational constants influenced by bulk curvature and matter coupling, with implications for early universe evolution.

Contribution

It introduces a comprehensive framework for braneworld cosmology with Gauss-Bonnet terms, showing how bulk curvature affects gravitational constants and matter interactions.

Findings

Gravitational and cosmological constants vary with time due to bulk curvature.

Bulk black hole mass influences the variation of these constants.

Matter-curvature coupling may impact early universe cosmology.

Abstract

We consider braneworld scenarios including the leading correction to the Einstein-Hilbert action suggested by superstring theory, the Gauss-Bonnet term. We obtain and study the complete set of equations governing the cosmological dynamics. We find they have the same form as those in Randall-Sundrum scenarios but with time-varying four-dimensional gravitational and cosmological constants. Studying the bulk geometry we show that this variation is produced by bulk curvature terms parameterized by the mass of a black hole. Finally, we show there is a coupling between these curvature terms and matter that can be relevant for early universe cosmology.