Condensation of a Classical Scalar Field After Inflation and Dark Energy
  In cosmological context, classical scalar fields are important ingredients for inflation models, many candidate models of dark energy, symmetry breaking and phase transition epochs, and their consequences such as baryo and lepto-genesis. We investigate the formation of these fields by studying the production of a light quantum scalar field during the decay of a heavy particle. For simplicity it is assumed to be a scalar too. We discuss the effects of the decay mode, the thermodynamical state of the decaying field, boundary conditions, and related physical parameters on the production and evolution of a condensate. For a simplified version of this model we calculate the asymptotic behaviour of the condensate and conditions for its contribution to the dark energy with an equation of state close to a cosmological constant. We also discus the role of the back-reaction from interactions with other fields and expansion of the Universe on the evolution of the condensate. 
Houri Ziaeepour