Primordial Black Holes

Abstract

In this chapter I give a personal overview of the new scenario of broad mass and clustered primordial black holes that could constitute all of the dark matter, be responsible for the binary black hole events detected with gravitational waves by LIGO/Virgo interferometers, and also for the microlensing events in our galaxy detected by OGLE and GAIA. I describe their plausible origin as quantum fluctuations during inflation, their clustering and evolution since their formation at the quark-hadron transition in the early universe, as well as their signatures, both cosmological and astrophysical. I make emphasis on the fact that this scenario does not require new physics beyond the Standard Model of particle physics. I then give an overview of the extremely rich phenomenology that this scenario opens for exploration in the next few decades, where a multi-probe, multi-scale, and multi-epoch approach is required to connect the different phenomena.