Branes and Black holes in Collision

TL;DR

This study investigates the collision between a brane and a black hole, revealing that high-energy collisions are less likely to perforate the brane and that domain wall erasure via black hole perforation is improbable in cosmological contexts.

Contribution

The paper introduces a numerical simulation of brane-black hole collisions, demonstrating the velocity-dependent perforation process and conditions under which domain walls might be erased.

Findings

Perforation depends on collision velocity, with high velocities preventing wall piercing.

Perforation likelihood increases only when string and wall energy scales are closely matched.

Domain walls with holes edged by strings are likely to eventually disappear.

Abstract

We study the collision of a brane with a black hole. Our aim is to explore the topology changing process of perforation of a brane. The brane is described as a field theoretical domain wall in the context of an axion-like model consisting of a complex scalar effective field theory with approximate U(1) symmetry. We simulate numerically the dynamics of the collision and illustrate the transition from the configuration without a hole to the pierced one with the aid of a phase diagram. The process of perforation is found to depend on the collisional velocity, and, contrary to our expectation, we observe that above a critical value of the velocity, the black hole has no chance to perforate the wall. That is: high energy collisions do not assist piercing. We also show that, only when the model parameters are fine-tuned so that the energy scale of the string is very close to that of the domain wall, the collision of the wall with the black hole has a possibility to provide a mechanism to erase domain walls, if the hole expands. However, in such cases, domain walls will form with many holes edged by a string and therefore disappear eventually. Therefore this mechanism is unlikely to be a solution to the cosmological domain wall problem, although it may cause some minor effects on the evolution of a domain wall network.