Cosmological dynamics of a phantom field

Abstract

We study the general features of a dynamics of a phantom field in the cosmological context. In the case of an inverse coshyperbolic potential, we demonstrate that the phantom field can successfully drive the observed current accelerated expansion of the Universe with the equation of state parameter ${w}_{\ensuremath{\varphi}}<\ensuremath{-}1.$ The de Sitter universe turns out to be the late time attractor of the model. The main features of the dynamics are independent of the initial conditions and the parameters of the model. The model fits the supernova data very well, allowing for $\ensuremath{-}2.4<{w}_{\ensuremath{\varphi}}<\ensuremath{-}1$ at a 95% confidence level.