GUT Baryogenesis after Preheating
  At the end of inflation the universe is frozen in a near zero-entropy state with energy density in a coherent scalar field and must be ``defrosted'' to produce the observed entropy and baryon number. We propose that the baryon asymmetry is generated by the decay of supermassive Grand Unified Theory (GUT) bosons produced non-thermally in a preheating phase after inflation. We show that baryogenesis is possible for an inflaton masses of order 10^{13} GeV and a GUT Higgs boson mass of order 10^{14} GeV, thus solving many drawbacks facing GUT baryogenesis in the old reheating scenario. 
Edward W. Kolb, Andrei Linde, and Antonio Riotto