Accelerated expansion of a universe containing a self-interacting   Bose-Einstein gas
  Acceleration of the universe is obtained from a model of non-relativistic particles with a short-range attractive interaction, at low enough temperature to produce a Bose-Einstein condensate. Conditions are derived for negative-pressure behavior. In particular, we show that a phantom-accelerated regime at the beginning of the universe solves the horizon problem, consistently with nucleosynthesis. 
German Izquierdo, Jaime Besprosvany