Primordial black holes as a dark matter candidate

The detection of gravitational waves from mergers of tens of Solar mass black hole binaries has led to a surge in interest in primordial black holes (PBHs) as a dark matter candidate. We aim to provide a (relatively) concise overview of the status of PBHs as a dark matter candidate, circa Summer 2020. First we review the formation of PBHs in the early Universe, focussing mainly on PBHs formed via the collapse of large density perturbations generated by inflation. Then we review the various current and future constraints on the present day abundance of PBHs. We conclude with a discussion of the key open questions in this field.

Automated summary

The detection of gravitational waves from mergers of tens of Solar mass black hole binaries has sparked interest in primordial black holes as a dark matter candidate. This overview provides insights into the formation of primordial black holes, current constraints on their present day abundance, and key open questions in the field as of Summer 2020.