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

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