Phantom Divide Crossing with General Non-minimal Kinetic Coupling

TL;DR

This paper introduces a dark energy model with a scalar field coupled non-minimally to curvature, demonstrating conditions and numerical evidence for crossing the phantom divide in the equation of state.

Contribution

It develops a novel dark energy framework with general non-minimal kinetic couplings and analyzes conditions for phantom divide crossing.

Findings

Conditions for phantom divide crossing derived

Numerical models show realization of crossing

Coupling terms influence dark energy dynamics

Abstract

We propose a model of dark energy consists of a single scalar field with a general non-minimal kinetic couplings to itself and to the curvature. We study the cosmological dynamics of the equation of state in this setup. The coupling terms have the form $\xi_{1} R f(\phi)\partial_{\mu}\phi\partial^{\mu}\phi$ and $\xi_{2} R_{\mu\nu}f(\phi)\partial^{\mu}\phi\partial^{\nu}\phi$ where $\xi_{1}$ and $\xi_{2}$ are coupling parameters and their dimensions depend on the type of function $f(\phi)$. We obtain the conditions required for phantom divide crossing and show numerically that a cosmological model with general non-minimal derivative coupling to the scalar and Ricci curvatures can realize such a crossing.