Phantom instability of viscous dark energy in anisotropic space-time

Abstract

Phantom dark energy is a proposal that explains the current observations that mildly favor the equation of state of dark energy ω de crossing −1 at 68 % confidence level. However, phantom fields are generally ruled out by ultraviolet quantum instabilities. To overcome this discrepancy, in this paper we propose a mechanism to show that how the presence of bulk viscosity in the cosmic fluid can temporarily drive the fluid into the phantom region (ω<−1). As time is going on, phantom decays and ultimately ω de approaches to −1. Then we show these quintessence and phantom descriptions of non-viscous and viscous dark energy and reconstruct the potential of these two scalar fields. Also a diagnostic for these models are performed by using the statefinder pairs {s,r}. All results are obtained in an anisotropic space-time which is a generalization of FLRW universe.