Creating vortons and three-dimensional skyrmions from domain-wall annihilation with stretched vortices in Bose-Einstein condensates

Abstract

We study a mechanism to create a vorton or three-dimensional skyrmion in phase-separated two-component BECs with the order parameters ${\ensuremath{\Psi}}_{1}$ and ${\ensuremath{\Psi}}_{2}$ of the two condensates. We consider a pair of a domain wall (brane) and an antidomain wall (antibrane) stretched by vortices (strings), where the ${\ensuremath{\Psi}}_{2}$ component with a vortex winding is sandwiched by two domains of the ${\ensuremath{\Psi}}_{1}$ component. The vortons appear when the domain wall pair annihilates. Experimentally, this can be realized by preparing the phase separation in the order ${\ensuremath{\Psi}}_{1}$, ${\ensuremath{\Psi}}_{2}$, and ${\ensuremath{\Psi}}_{1}$ components, where the nodal plane of a dark soliton in ${\ensuremath{\Psi}}_{1}$ component is filled with the ${\ensuremath{\Psi}}_{2}$ component with vorticity. By selectively removing the filling ${\ensuremath{\Psi}}_{2}$ component gradually with a resonant laser beam, the collision of the brane and antibrane can be made, creating vortons.