Quantum quenches and spin dynamics in spin-orbit coupled Bose-Einstein condensates

Juan Wang, Zhenze Fan, Yan Li

Zi-Fa Yu, Ji-Ming Gao, Ai‐Xia Zhang +2 more

Tian-Shu Deng, Wei Zhang, Wei Yi +1 more

We study the quench dynamics of a Bose-Einstein condensate under a Raman-assisted synthetic spin-orbit coupling. To model the dynamical process, we adopt a self-consistent Bogoliubov approach, which is equivalent to applying the time-dependent Bogoliubov--de Gennes equations. We investigate the dynamics of the condensate fraction as well as the momentum distribution of the Bose gas following a sudden change of system parameters. Typically, the system evolves into a steady state in the long-time limit, which features an oscillating momentum distribution and a stationary condensate fraction. We investigate how different quench parameters such as the inter- and intraspecies interactions and the spin-orbit-coupling parameters affect the condensate fraction in the steady state. Furthermore, we find that the time average of the oscillatory momentum distribution in the long-time limit can be described by a generalized Gibbs ensemble with two branches of momentum-dependent Gibbs temperatures. Our study is relevant to the experimental investigation of dynamical processes in a spin-orbit-coupled Bose-Einstein condensate.

Wai Ho Tang, Shizhong Zhang

Sheng Liu, Yongsheng Zhang

We consider the phase transition dynamics of a trapped Bose-Einstein condensate subject to Raman-type spin-orbit coupling. By tuning the coupling strength the condensate is taken through a second-order phase transition into an immiscible phase. We observe the domain wall defects produced by a finite speed quench is described by the Kibble-Zurek mechanism, and quantify a power-law behavior for the scaling of domain number and formation time with the quench speed.

Brandon Anderson, Tudor D. Stanescu, Victor M. Galitski