Quadratic reheating

The reheating process for the inflationary scenario is investigated phenome nologically. The decay of the oscillating massive inflaton field into light bosons is modeled after an out of equilibrium mixture of interacting fluid s within the framework of irreversible thermodynamics. Self-consistent, ana lytic results for the evolution of the main macroscopic magnitudes like tem perature and particle number densities are obtained. The models for linear and quadratic decay rates are investigated in the quasiperfect regime. The linear model is shown to reheat very slowly while the quadratic one is show n to yield explosive particle and entropy production. The maximum reheating temperature is reached much faster and its magnitude is comparable with th e inflaton mass.