The Bloch oscillations of spin-orbit coupled Bose-Einstein condensates in deep optical lattices

We study the ground state and the Bloch oscillations of the spin-orbit coupled Bose-Einstein condensates in one-dimensional deep optical lattices. The phase transition between the zero-momentum phase and the plane-wave phase in untilted deep optical lattices is studied analytically. The Bloch oscillations in tilted lattices started in different ground state phases are analyzed. It is found that the Bloch dynamics is harmonic (anharmonic) in the zero-momentum phase (plane-wave phase). Furthermore, the modification of the Bloch oscillations induced by spin-orbit coupling, tunnelling coefficient and the external force (the inclination of the tilt) is revealed. In addition, the analytical condition for emerging the long-lived Bloch oscillations is obtained and the corresponding diagram in parameter space is provided. Particularly, we find that the spin-orbit coupling can extend the duration of the Bloch oscillations in the plane-wave phase. We provide an effective method to manipulate the Bloch dynamics in the deep optical lattices. Copyright (C) 2022 EPLA