Primordial Black Holes and Wormholes from Domain Wall Networks

Understand

Domain walls (DWs) are topological defects originating from phase transitions in the early universe.

• In the presence of an energy imbalance between distinct vacua, enclosed DW cavities shrink until the entire network disappears.
• By studying the dynamics of thin-shell bubbles in General Relativity, we demonstrate that closed DWs with sizes exceeding the cosmic horizon tend to annihilate later than the average.
• This delayed annihilation allows for the formation of large overdensities, which, upon entering the Hubble horizon, eventually collapse to form Primordial Black Holes (PBHs).