Radiation emission during the erasure of magnetic monopoles

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 et al. [Phys. Rev. Lett. 80, 2281 (1998)]. 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 postinflationary 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.