Kyohei Mukaida (Kavli IPMU, Japan)
After inflation, inflaton converts its huge energy into radiation to create the hot Universe, which is referred to as reheating. Naively, one might guess that radiation produced via reheating soon attains the thermal distribution within the Hubble time. Under this instantaneous thermalization assumption, many attractive thermal mechanisms were proposed so far; such as thermal leptogenesis, thermal dark matter production, to name a few. In this talk, we examine this naive expectation, i.e. instantaneous thermalization, in the case of reheating via perturbative inflaton decay. We will show how the produced plasma becomes thermalized, and also discuss its implications on heavy particle production and symmetry restoration in the early Universe.