Braneworld models with a non-minimally coupled phantom bulk field: a simple way to obtain the -1-crossing at late times

TL;DR

This paper explores braneworld cosmological models with a non-minimally coupled phantom bulk field, demonstrating a natural mechanism for the dark energy equation-of-state to cross the -1 boundary at late times.

Contribution

It introduces a general framework showing that non-minimal coupling induces dynamical dark energy capable of crossing the -1 threshold without specific parameter constraints.

Findings

The model naturally achieves -1-crossing of dark energy equation-of-state.

Non-minimal coupling induces effective bulk-brane interaction affecting cosmic evolution.

An approximate analytical solution illustrating the crossing behavior is provided.

Abstract

We investigate general braneworld models, with a non-minimally coupled phantom bulk field and arbitrary brane and bulk matter contents. We show that the effective dark energy of the brane-universe acquires a dynamical nature, as a result of the non-minimal coupling which provides a mechanism for an indirect "bulk-brane interaction" through gravity. For late-time cosmological evolution and without resorting to special ansatzes or to specific areas of the parameter space, we show that the -1-crossing of its equation-of-state parameter is general and can be easily achieved. As an example we provide a simple, but sufficiently general, approximate analytical solution, that presents the crossing behavior.