Prof. Mikko Laine
AEC, ITP, University of Bern, Switzerland

Abstract: In the development of the big bang theory, it was originally thought that the universe may start from an infinite temperature. From the modern perspective, this is hardly plausible, and the very early universe may rather resemble a 'cold' quantum state. The current best picture is that this quantum state underwent a period of exponential expansion, called inflation, which ended in a so-called reheating period, which initiated the conventional hot big bang. It would be nice to probe such physics empirically. In this talk, I outline how gravitational-wave observations may one day offer for a possibility to measure or constrain the maximal temperature, reached in the early universe just after the reheating epoch.