Late-time acceleration and Phantom Divide Line Crossing with Non-minimal Coupling and Lorentz Invariance Violation

TL;DR

This paper explores two dark energy models, one with nonminimal coupling and Lorentz invariance, and another with Lorentz violation, demonstrating their ability to produce late-time acceleration and crossing of the phantom divide line.

Contribution

It introduces and compares two alternative dark energy models, highlighting the role of nonminimal coupling and Lorentz invariance violation in cosmic acceleration.

Findings

Nonminimally coupled scalar field can cross the cosmological constant line.

Lorentz invariance violation enables accelerated expansion and phantom crossing.

Minimal coupling without Lorentz violation cannot achieve these features.

Abstract

We consider two alternative dark energy models: a Lorentz invariance preserving model with a nonminimally coupled scalar field and a Lorentz invariance violating model with a minimally coupled scalar field. We study accelerated expansion and dynamics of equation of state parameter in these scenarios. While a minimally coupled scalar field has not the capability to be a successful dark energy candidate with cosmological constant line crossing, a nonminimally coupled scalar field in the presence of Lorentz invariance or a minimally coupled scalar field with Lorentz invariance violation have this capability. In the later case, accelerated expansion and phantom divide line crossing are the results of interactive nature of this Lorentz violating scenario.