Dark Energy Models With Variable Equation Of State Parameter

Abstract

Two variable $\Lambda$ models, viz. $\Lambda \sim (\dot a/a)^2$ and $\Lambda \sim \rho$ have been studied under the assumption that the equation of state parameter $\omega$ is a function of time. The selected $\Lambda$ models are found to be equivalent both in four and five dimensions. The possibility of signature flip of the deceleration parameter is also shown.