Brane-world cosmology and varying $G$

TL;DR

This paper explores a brane-world cosmological model with a bulk scalar field where the Newton coupling G varies over time, and uses observational bounds to constrain the model's parameters.

Contribution

It introduces a brane-world model linking brane tension to G, leading to natural G variation and constrains it using nucleosynthesis and CMB data.

Findings

G variation is tightly constrained by nucleosynthesis.

CMB data provides the strongest bounds on model parameters.

Model links brane tension directly to Newton's G.

Abstract

We consider a brane-world cosmological model coupled to a bulk scalar field. Since the brane tension turns out to be proportional to Newton coupling $G$, in such a model a time variation of $G$ naturally occurs. By resorting to available bounds on the variation of $G$, the parameters of the model are constrained. The constraints coming from nucleosynthesis and CMB result to be the severest ones.