Some Consequences of Dark Energy Density varying Exponentially with Scale Factor

Abstract

In this paper we have explored the consequences of a model of dark energy with its energy density varying exponentially with the scale factor. We first consider the model with ${\rho }_{\varphi }\propto e^{\kappa a}$, where $\kappa$ is a constant. This is a kind of generalisation of the cosmological constant model with $\kappa =0$. We show that such an exponentially varying dark energy density with the scale factor naturally leads to an equivalent phantom field. We also consider a model with ${\rho }_{\varphi }\propto e^{\kappa /a}$ and we show that this also naturally leads to an equivalent phantom field.

22 pages, 6 figures