Primordial Black Holes from Non-Equilibrium Second Order Phase Transition

TL;DR

This paper explores how primordial black holes could form from collapsing domain walls created during a second order phase transition in the early universe, driven by scalar field dynamics during inflation.

Contribution

It introduces a mechanism where vacuum domain walls formed during inflation can collapse into black holes, providing a new pathway for primordial black hole formation.

Findings

Domain walls can collapse into black holes under certain conditions.

Scalar field evolution during inflation can produce suitable domain structures.

This mechanism can generate massive primordial black holes.

Abstract

The collapse of sufficiently large closed domain wall produced during second order phase transition in the vacuum state of a scalar field can lead to the formation of black hole. The origin of domain walls with appropriate size and energy density could be a result of evolution of an effectively massless scalar field at the inflational epoch. We demonstrate that in this case the situation is valued when there are compact domains of less favorable vacuum surrounded by a sea of another vacuum. Each domain has a surface composed of vacuum wall that stores a significant amount of energy, and can collapse into the black hole. This offers the way of massive primordial black holes formation in the early Universe.