Bianchi cosmologies with diffusion
We apply the dynamical systems approach to Bianchi cosmologies filled with a tilted {\gamma}-fluid undergoing velocity diffusion on a scalar field. We analyze the system of Einstein field equations coupled with the diffusion equations both analytically and numerically. We determine the future attractors, describe the late-time behaviour of the models and investigate the effects caused by diffusion. We show that although cosmologies with diffusion are in some aspects similar to those with a positive cosmological constant, the late-time dynamics of these models can be substantially different. For example, we demonstrate that in presence of diffusion all fluids with {\gamma<3/2}, which includes the cases of largest physical importance, namely dust {(\gamma=1)} and radiation {(\gamma=4/3)} are asymptotically non-tilted.
The presentation is based on the two recent articles:
arXiv:1402.2785 (submitted)
arXiv:1402.6864 (submitted)