Effect of the Chameleon Scalar Field on Brane Cosmological Evolution

TL;DR

This paper explores how a chameleon scalar field in a brane world model influences cosmic evolution, leading to late-time acceleration and crossing the phantom barrier without exotic matter.

Contribution

It introduces a brane model with a chameleon scalar field affecting cosmological dynamics and demonstrates late-time acceleration and phantom crossing.

Findings

Universe exhibits late-time accelerating expansion.

Crosses the phantom barrier without exotic matter.

Energy transfer direction constrained by thermodynamics.

Abstract

We have investigated a brane world model in which the gravitational field in the bulk is described both by a metric tensor and a minimally coupled scalar field. This scalar field is taken to be a chameleon with an appropriate potential function. The scalar field interacts with matter and there is an energy transfer between the two components. We find a late-time asymptotic solution which exhibits late-time accelerating expansion. We also show that the Universe recently crosses the phantom barrier without recourse to any exotic matter. We provide some thermodynamic arguments which constrain both the direction of energy transfer and dynamics of the extra dimension.