Stable Solitons in Three Dimensional Free Space: Self-Trapped Bose-Einstein Condensates with Spin-Orbit Coupling

TL;DR

This paper demonstrates the existence of stable three-dimensional solitons in free space within binary Bose-Einstein condensates that incorporate spin-orbit coupling, showing stability despite supercritical collapse.

Contribution

It introduces stable 3D solitons in free space with spin-orbit coupling, a novel finding in the context of self-attracting Bose-Einstein condensates.

Findings

Stable semi-vortex and mixed-mode solitons identified

Solitons remain stable against perturbations, motion, and collisions

Existence confirmed through variational and numerical methods

Abstract

By means of variational methods and systematic numerical analysis, we demonstrate the existence of stable solitons in three-dimensional (3D) free space, in the context of binary atomic condensates combining contact self-attraction and spin-orbit coupling, which can be engineered by available experimental techniques. Depending on the relative strength of the intra- and inter-component attraction, the stable solitons feature a semi-vortex or mixed-mode structure. In spite of the fact that the local cubic self-attraction gives rise to the supercritical collapse in 3D, the solitons are stable against random perturbations, motion, and collisions.