Staggered quantum Kármán vortex street in a two-component dipolar Bose–Einstein condensate

The dynamics of a two-component dipolar Bose–Einstein condensate, which consists of two different dipolar bosonic atoms, through a moving obstacle potential is numerically studied. The numerical results show that the parametric regions of the staggered quantum Kármán vortex street and related vortex shedding patterns depend strongly on the obstacle width d, moving velocity υ, and dipole–dipole interaction strength addjk and reveal a spatially staggered half-quantum vortex street with anti-phase ordering between the two components. Moreover, the phase diagrams of various vortex shedding patterns under different obstacle potential widths and moving velocities are obtained. By analyzing the instantaneous drag force acting on the obstacle potential, the contribution of various vortex shedding to the drag force is obtained. As the dipolar interaction strength increases, the parameter range of vortex street decreases, and the shedding order of the vortex patterns also changes. The special two-component system considered here opens up another way to explore the vortex dynamics of dipolar quantum gases.