Reviving PBHs: primordial black holes from supercooled phase transitions revisited

Primordial black holes, hypothetical objects that may have formed in the early Universe through the interplay between high-energy physics and gravity, are very appealing candidates for dark matter. In this seminar, I will discuss their formation as a result of the collapse of energy density fluctuations originating from supercooled first-order phase transitions. I will present the formalism that we use to track the evolution of such fluctuations in a fully covariant manner, explicitly incorporating the spacetime metric perturbations. I will show which aspects of the phase transition drive the growth of density fluctuations and their gravitational collapse, and identify the transitions for which the produced population of primordial black holes may constitute a significant fraction of the total dark matter abundance.