Extended Chaplygin Gas in Horava-Lifshitz Gravity

Abstract

In this paper, we investigate cosmological models of the extended Chaplygin gas in a universe governed by Horava-Lifshitz gravity. The equation of state for an extended Chaplygin gas is a \((n+2)\)-variable equation determined by \(A_{n}\), \(\alpha\), and \(B\). In this work, we are interested to the case of second order \((n=2)\) equation of state which recovers quadratic barotropic equation of state. In that case there are four free parameters. We solve conservation equation approximately and obtain energy density in terms of scale factor with mentioned free parameters. Under some assumptions we relate free parameters to each other to have only one free independent parameter \((A_{2})\). It help us to obtain explicit expression for energy density in terms of scale factor. The allowed values of the second order extended Chaplygin gas parameter is fixed using the recent astrophysical and cosmological observational data. Thermodynamics of the model investigated based on the first and second law of thermodynamics.