Non-Thermal Phase Transitions after Inflation

Abstract

At the first stage of reheating after inflation, parametric resonance may rapidly transfer most of the energy of an inflaton field $\varphi$ to the energy of other bosons. We show that quantum fluctuations of scalar and vector fields produced at this stage are much greater than they would be in a state of thermal equilibrium. This leads to cosmological phase transitions of a new type, which may result in a copious production of topological defects and in a secondary stage of inflation after reheating.

Comments: 4 pages, an improved version to be published in Phys. Rev. Lett