Spin dynamics of a spin-orbit-coupled Bose-Einstein condensate in a shaken harmonic trap

摘要

We propose a mechanism to realize nontrivial spin dynamics in a one-dimensional spin-orbit-coupled Bose- Einstein condensate by abruptly shaking the harmonic trap. Continuously varying the shaking strength, it is found that the Bose-Einstein condensate may exhibit exotic nonequilibrium spin dynamics. Specifically, at some special values of the shaking strength, the time-averaged spin polarization shows sharp resonant peaks, whereas it tends to be zero at any other positions. Furthermore, the spacings between any two nearest peaks depend only on the system parameters and are thus identical to each other. By simplifying this time-dependent system to an exactly solvable "quantum quench" model, we show that the essential physics behind the exotic spin dynamics comes from periodic suppressing and enhancing of the out-of-phase interference. It is further shown that the presented physical picture persists under weak atomic interactions. This work may shed light on the ongoing research of spin-based quantum control and quantum information.