A First Principles Warm Inflation Model that Solves the Cosmological   Horizon/Flatness Problems
  A quantum field theory warm inflation model is presented that solves the horizon/flatness problems. The model obtains, from the elementary dynamics of particle physics, cosmological scale factor trajectories that begin in a radiation dominated regime, enter an inflationary regime and then smoothly exit back into a radiation dominated regime, with nonnegligible radiation throughout the evolution. 
Arjun Berera, Marcelo Gleiser, Rudnei O. Ramos