Baryonic handles: Skyrmions as open vortex strings on a domain wall

TL;DR

This paper explores Skyrmion solutions in a BEC-inspired Skyrme model near a domain wall, revealing complex vortex structures and their interactions, with implications for stability and energy preferences of these topological solitons.

Contribution

It introduces new vortex handle configurations and analyzes their stability and interactions in a BEC-Skyrme model near a domain wall.

Findings

Domain wall provides strong binding energy for Skyrmions.

Most stable 2-Skyrmion is a torus-shaped vortex junction.

Metastable configurations include twisted vortex handles and rings.

Abstract

We consider the BEC-Skyrme model which is based on a Skyrme-type model with a potential motivated by Bose-Einstein condensates (BECs) and, in particular, we study the Skyrmions in proximity of a domain wall that inhabits the theory. The theory turns out to have a rich flora of Skyrmion solutions that manifest themselves as twisted vortex rings or vortons in the bulk and vortex handles attached to the domain wall. The latter are linked open vortex strings. We further study the interaction between the domain wall and the Skyrmion and between the vortex handles themselves as well as between the vortex handle and the vortex ring in the bulk. We find that the domain wall provides a large binding energy for the solitons and it is energetically preferred to stay as close to the domain wall as possible; other configurations sticking into the bulk are metastable. We find that the most stable 2-Skyrmion is a torus-shaped braided string junction ending on the domain wall, which is produced by a collision of two vortex handles on the wall, but there is also a metastable configuration which is a doubly twisted vortex handle produced by a collision of a vortex handle on the wall and a vortex ring from the bulk.