Nonlinear bulk viscosity and the stability of accelerated expansion in FRW spacetime

Abstract

In the context of dark energy solutions, we consider a Friedmann---Robertson---Walker spacetime filled with a noninteracting mixture of dust and a viscous fluid, for which the bulk viscosity is governed by the nonlinear model proposed in [R. Maartens and V. M\'endez, Phys. Rev. D 55, 1937 (1997)]. Through a phase-space analysis of the equivalent dynamical system, the existence and stability of critical solutions are established, and the respective scale factors are computed. The results point toward the possibility of describing the current accelerated expansion of the Universe by means of the above-mentioned nonlinear model for viscosity.