Nonlinear dynamics of tunable spin-orbit coupled Bose-Einstein condensates in deep optical lattices

We discuss the localization and spin dynamics of tunable spin-orbit coupled Bose-Einstein condensates in deep optical lattices. Rich localized phenomena (breather, soliton, self-trapping, and diffusion) are observed. The critical conditions for occurring different localized states are obtained analytically and confirmed numerically. Under the critical conditions, we observe localized states with fixed initial spin polarization. When the critical condition is not satisfied, because of spin-momentum locking, quenching of Raman coupling from soliton state excites spin dynamics. If initially the soliton is in a nearly unpolarized (polarized) state, persistent (damped) spin dynamics is excited. The system finally transforms to a new polarized state in the damped spin dynamics. The localization and spin dynamics can be well controlled by periodic modulation of Raman coupling. © 2022 Elsevier B.V.