Overlaps at the Frontiers of
Astrophysics, Cosmology and Particle Physics

Dissipative effects during inflation can be introduced by coupling the inflaton field to light degrees of freedom. Assuming thermalization and temporarily non-negligible radiation density during inflation, a localized enhancement of the primordial power spectrum can appear due to stochastic dynamics. This enhancement may lead to primordial black holes production as well as a stochastic background of gravitational waves. If these black holes constitute a significan fraction of the dark matter, the associated gravitational waves signal would be potentially observable by LISA. The calculation of the primordial power spectrum in this setup differs from the usual one in standard single-field inflation, mainly due to the stochastic nature of the radiation source of fluctuations. I will present three different (and mutually consistent) approaches to solve this problem.

Based on arXiv:2208.14978