Hubble Induced Mass in Radiation Dominated Universe
arXiv:1112.5823 · doi:10.1016/j.physletb.2012.03.069
Abstract
We reconsider the effective mass of a scalar field which interact with visible sector via Planck-suppressed coupling in supergravity framework. We focus on the radiation-dominated (RD) era after inflation. In this era, the effective mass is given by thermal average of interaction terms. To make our analysis clear, we rely on Kadanoff-Baym equations to evaluate the thermal average. We find that, in RD era, a scalar field acquires the effective mass of the order of $H$.
10 pages, v2:minor corrections and a reference added, v3:a footnote added, version accepted by PLB