Dark energy and dissipation
  Most of the models leading to a current state of cosmic accelerated expansion fail to address the coincidence problem, i.e., that the dark energy density and the energy density of the matter fluid are of the same order precisely today. We show that a way to drive late acceleration and simultaneously solve the aforesaid problem is assuming the matter fluid dissipative[1]. 
Diego Pavon, Luis P. Chimento, Alejandro S. Jakubi