Spin-orbit-coupling stabilization of a collapsing binary Bose-Einstein condensate

Abstract

We study the stability of a spin-orbit-coupled binary Bose-Einstein condensate. It is known that a trapped binary Bose-Einstein condensate will collapse when the interatomic attraction is beyond the threshold. We demonstrate both analytically and numerically that instead of collapse such a system can be stabilized by spin-orbit coupling and Raman coupling. The stability criteria and stability diagram in full parameter space are presented analytically. The stabilizing mechanism is revealed explicitly: the spin-orbit coupling and Raman coupling generate an effective interatomic repulsion, which changes the stability criteria, neutralizes the mean-field attraction, and stabilizes the system against collapse. Interestingly, the generated effective interatomic repulsion is determined by spin-orbit coupling and Raman coupling. That is, a quantitative theoretical evidence for controlling the stability of the system is provided, which can be realized easily in current experiments.