Physical Review Letters
A quantum field theory warm inflation model is presented that solves the horizon and 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 non-negligible radiation throughout the evolution.
Berera, Arjun; Gleiser, Marcelo; and Ramos, Rudnei O., "A First Principles Warm Inflation Model that Solves the Cosmological Horizon and Flatness Problems" (1999). Open Dartmouth: Faculty Open Access Articles. 2018.