Variable Brane Tension and Dark Energy

TL;DR

This paper explores a braneworld model with variable brane tension where matter mimics dark energy and a scalar field representing G acts as matter, matching standard cosmology and unifying cosmic acceleration phases.

Contribution

It introduces a novel braneworld scenario with variable brane tension that reproduces standard cosmological equations and unifies early and late cosmic acceleration.

Findings

Matter acts as dark energy in the model.

The scalar field G behaves as matter.

The Friedmann equation matches standard GR with a cosmological constant.

Abstract

In this letter, we show that in a particular braneworld scenario with variable brane tension, we obtain matter acting as dark energy while the gravitational constant $G$ promoted to a scalar field on the brane plays the role of matter (both in the sense they have an 'effective' Equation of State equivalent to that of dark energy and matter respectively). This result is interpreted from the Friedmann equation obtained from our model that exactly matches the standard Friedmann equation of General Relativity with a cosmological constant $\Lambda$ in terms of the aforementioned quantities. The universe is assumed to consist of only matter and dark energy in this model which is a good approximation for our universe. We also propose a way to unify early and late-time cosmic acceleration.