Primordial black holes and induced gravitational waves

Primordial black holes (PBHs) can generically form through the collapse of enhanced cosmological perturbations, constituting in some specific mass ranges a viable candidate for dark matter. Interestingly enough, the enhanced cosmological perturbations which collapse to form PBHs as well as the PBH energy density perturbations themselves can produce a stochastic gravitationalwave (GW) background induced by second-order gravitational interactions, which can be detectable in GW observatories.

In this talk, after introducing initially the motivation for the physics of PBHs and the associated to them GW signals I will focus afterwards on the ultra-light PBH mass range and its induced GW signatures through which one can probe the physics of the primordial Universe. Finally, I will discuss as well GWs induced by vector metric perturbations sourced by primordial magnetic fields.