Ground-State Dirac Monopole

TL;DR

This paper theoretically demonstrates that a Dirac monopole-like defect can be the ground state in a spin-1 Bose-Einstein condensate, revealing new topological phenomena and dynamics.

Contribution

It introduces a novel ground-state monopole in a spinor BEC, distinct from traditional monopoles attached to Dirac strings, and explores its dynamics after magnetic field removal.

Findings

Ground-state monopole forms a point with reversed vortex circulation.

Monopole dynamics show emergence of antimonopoles after field removal.

The scheme is feasible with current experimental techniques.

Abstract

We show theoretically that a monopole defect, analogous to the Dirac magnetic monopole, may exist as the ground state of a dilute spin-1 Bose-Einstein condensate. The ground-state monopole is not attached to a single semi-infinite Dirac string, but forms a point where the circulation of a single vortex line is reversed. Furthermore, the three-dimensional dynamics of this monopole defect are studied after the magnetic field pinning the monopole is removed and the emergence of antimonopoles is observed. Our scheme is experimentally realizable with the present-day state of the art.