Speaker
Description
One possible mechanism for the formation of primordial black holes (PBHs)
is the collapse of domain walls. Previous theoretical models considered PBH
formation in the spherical approximation, whereas full field-theoretic
simulations of non-spherical domain walls clusters are too computationally
demanding to accumulate sufficient statistics.
In this work, we derive the equations of motion of a domain wall in the
thin-wall approximation and propose a numerical method for evolving the
wall surface using triangular mesh algorithms. For prescribed field configurations of a cluster, the method yields the differential mass spectrum of the resulting PBHs.
Based on a Monte Carlo ensemble, we obtain $dN/dM \propto M^{-\alpha}$
with $\alpha = 2.31^{+0.01}_{-0.02}$, significantly larger than the
theoretical value $\alpha \approx 1.75$ for spherical-wall collapse,
indicating a larger fraction of low-mass PBHs. This deviation is
presumably due to the fragmentation of walls with complex geometry, which is absent
in the spherical approximation.
