Radiation Emission during the Erasure of Magnetic Monopoles

TL;DR

This paper investigates the process of magnetic monopole erasure during collisions with domain walls in an SU(2) gauge theory, revealing radiation emission and implications for cosmology and gauge theory phases.

Contribution

It provides numerical simulations demonstrating monopole erasure by domain walls and analyzes the emitted radiation, offering new insights into gauge theories and cosmological monopole abundance.

Findings

Monopoles are always erased upon collision with domain walls.

Electromagnetic radiation is emitted during the erasure process.

Monopoles never pass through the wall, explained by entropy suppression.

Abstract

We study the interactions between 't Hooft-Polyakov magnetic monopoles and the domain walls formed by the same order parameter within an $SU(2)$ gauge theory. We observe that the collision leads to the erasure of the magnetic monopoles, as suggested by Dvali, Liu, and Vachaspati. The domain wall represents a layer of vacuum with un-Higgsed $SU(2)$ gauge symmetry. When the monopole enters the wall, it unwinds, and the magnetic charge spreads over the wall. We perform numerical simulations of the collision process and in particular analyze the angular distribution of the emitted electromagnetic radiation. As in the previous studies, we observe that erasure always occurs. Although not forbidden by any conservation laws, the monopole never passes through the wall. This is explained by entropy suppression. The erasure phenomenon has important implications for cosmology, as it sheds a very different light on the monopole abundance in post-inflationary phase transitions and provides potentially observable imprints in the form of electromagnetic and gravitational radiation. The phenomenon also sheds light on fundamental aspects of gauge theories with coexisting phases, such as confining and Higgs phases. Additionally to the figures, the results of the numerical simulations can be found in the following video: https://youtu.be/JZaXUYikQbo