Variable Brane Tension and Dark Energy

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.