Thermal stability of Chaplygin gas models and Chevallier–Polarski–Linder parametrization

Abstract

We consider the fractal universe model with timelike fractal profile in flat Friedmann–Robertson–Walker (FRW) universe model and check the thermodynamic stability of various dark energy models. These dark energy models include family of Chaplygin gas models (such as generalized Chaplygin gas, modified Chaplygin gas, generalized cosmic Chaplygin gas, variable modified Chaplygin gas) and parametrized equation-of-state (Chevallier–Polarski–Linder) model. To check the stability of these models in fractal framework thermodynamically, we construct total equation-of-state parameter for each case. The conditions to check the stability of models depending on some thermodynamic quantities yield three conditions on this parameter. We graphically check the behavior of the equation-of-state parameter along with stability of each model. It is concluded that the dark energy models are thermodynamically stable under appropriate choices of model parameters.