EXACT SOLUTIONS OF A FLAT FULL CAUSAL BULK VISCOUS FRW COSMOLOGICAL MODEL THROUGH FACTORIZATION

Abstract

We study the classical flat full causal bulk viscous Friedmann–Robertson–Walker (FRW) cosmological model through the factorization method. The method shows that there exists a relationship between the viscosity parameter s and the parameter γ entering the equations of state of the model. Also, the factorization method allows to find some new exact parametric solutions for different values of the viscous parameter s. Special attention is given to the well-known case s = 1/2, for which the cosmological model admits scaling symmetries. Furthermore, some exact parametric solutions for s = 1/2 are obtained through the Lie group method.