The field descriptions for thermal-equilibrium Friedmann–Robertson–Walker universe

Abstract

In this paper, we show the simple expression for the energy density of the thermal-equilibrium Friedmann–Robertson–Walker (TEFRW) universe and study the problem how to describe it by using some field models. We analyze the properties of the quintessence field in the quintessence model, calculate the tachyon potential in the tachyon model and point out that the latter model cannot give the whole description for the TEFRW universe. It is found that the two-field model can be responsible for describing the whole evolution process of the TEFRW universe.