Non-minimal Quintessence: Dynamics and coincidence problem

TL;DR

This paper explores a scalar-tensor cosmological model where dark matter and dark energy interact, providing a natural explanation for their comparable densities today by analyzing the dynamics within Brans-Dicke theory.

Contribution

It demonstrates how conformal coupling in scalar-tensor theories can address the coincidence problem through specific dynamical behavior.

Findings

Dark energy and dark matter densities become comparable today

The model offers a natural mechanism for the coincidence problem

Dynamics support a stable late-time attractor solution

Abstract

Brans--Dicke scalar--tensor theory provides a conformally coupling of the scalar field with gravity in Einstein's frame. This model is equivalent to an interacting quintessence in which dark matter is coupled to dark energy. This provides a natural mechanism to alleviate the coincidence problem. We investigate the dynamics of this model and show that it leads to comparable dark energy and dark matter densities today.