Decay of an isolated monopole into a Dirac monopole configuration

TL;DR

This paper numerically investigates the decay process of isolated monopoles in a spin-1 Bose-Einstein condensate, revealing a transition from a polar phase with a vortex ring to a ferromagnetic phase with a Dirac monopole.

Contribution

It provides a detailed numerical analysis of monopole decay dynamics and uncovers the formation of a Dirac monopole in the ferromagnetic phase post-decay.

Findings

Monopole core contains a half-quantum vortex ring.

Dynamical quantum phase transition destroys the polar phase.

Ferromagnetic order exhibits a Dirac monopole in synthetic magnetic field.

Abstract

We study numerically the detailed structure and decay dynamics of isolated monopoles in conditions similar to those of their recent experimental discovery. We find that the core of a monopole in the polar phase of a spin-1 Bose-Einstein condensate contains a small half-quantum vortex ring. Well after the creation of the monopole, we observe a dynamical quantum phase transition that destroys the polar phase. Strikingly, the resulting ferromagnetic order parameter exhibits a Dirac monopole in its synthetic magnetic field.