Eur. Phys. J. C (2008) 58: 499-510
https://doi.org/10.1140/epjc/s10052-008-0767-3

Regular Article - Theoretical Physics

Late-time acceleration and phantom divide line crossing with non-minimal coupling and Lorentz-invariance violation

¹ Department of Physics, Faculty of Basic Sciences, University of Mazandaran, P.O. Box 47416-1467, Babolsar, Iran
² Research Institute for Astronomy and Astrophysics of Maragha, P.O. Box 55134-441, Maragha, Iran

^* e-mail: knozari@umz.ac.ir

Received: 24 July 2008
Revised: 8 September 2008
Published online: 25 October 2008

Abstract

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