The dynamical stripes in spin–orbit coupled Bose–Einstein condensates with Josephson junctions

Abstract

The Josephson dynamics of the Bose–Einstein condensation with Raman-induced spin–orbit coupling is investigated. A quasi-1D trap is divided into two reservoirs by an optical barrier. Before the tunneling between the reservoirs is turned on, the system stays in its equilibrium ground state, which displays a rich phase diagram for different spin–orbit coupling parameters and interaction strengths. In this work we focus on the plane wave phase and the stripe phase. Our calculation shows that, when the tunneling is turned on, the plane wave phase evolves into a dynamical stripe phase, that is, the density of the particle changes from uniform to periodically modulated. Basically, this stripe is described by a sine function and the wave length, the amplitude and the initial phase of the function are all varying with time. If the system stays in stripe phase initially, the stripes become “sliding” when the tunneling is turned on, which reflects the running of one of the phases of the wave function.