Moving obstacle potential in a spin-orbit-coupled Bose-Einstein condensate

Abstract

We investigate the dynamics around an obstacle potential moving in the plane-wave state of a pseudospin-1/2 Bose-Einstein condensate with Rashba spin-orbit coupling. We numerically investigate the dynamics of the system and find that it depends not only on the velocity of the obstacle but also significantly on the direction of obstacle motion, which are verified by a Bogoliubov analysis. The excitation diagram with respect to the velocity and direction is obtained. The dependence of the critical velocity on the strength of the spin-orbit coupling and the size of the obstacle is also investigated.

Spin-orbit coupled spin-1 Bose-Einstein condensate flow past an obstacle in the presence of a Zeeman field

“…In this section, we give our numerical results of our timedependent GP equation. Compared with the ideal case discussed above, for a finite-size obstacle, the Bogoliubov excitations can be expected to be qualitatively unchanged, but the critical velocity v c generally decreases [74,77,78]. Besides Bogoliubov excitations in momentum space, when the spinor BEC is disturbed by a moving obstacle, vortex excitations in real space can be induced.…”

“…First, we consider the case of θ B = π/2, i.e., the ZF is applied along x direction. Vortex excitations could be shed from the fast moving obstacle [68,74]. When the obstacle is also moving along x direction, vortex-antivortex pairs are generated periodically behind it for each component.…”

“…Recently, a variety of studies were performed on the dynamics of a scalar BEC flow past an obstacle, especially after the experimental observation of the induced vortex-antivortex pairs [60,61], which have been shown to exhibit extraordinary behaviors [62][63][64][65][66][67][68][69][70]. Nevertheless, much less attention has been paid on the corresponding case of a spinor BEC flow past an obstacle [71][72][73][74], which is expected to be capable of revealing more exotic quantum * Electronic address: anjin@nju.edu.cn states due to the interplay among SO coupling, spin exchange and other competing interactions.…”

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

“…Numerical simulations based on the Gross-Pitaevskii equation (GPE) have shown that the vortex dipoles or vortex-antivortex pairs can be nucleated when a superfluid moves past an obstacle faster than the critical velocity, above which vortex shedding induces the drag force [3][4][5][6][7][8]. Moreover, the vortex dipoles can also be generated by the moving Gaussian potential [9,10], the oscillating Gaussian potential [11] in a condensate, the circular motion of a Gaussian potential stirring the condensate [12], or the moving circular potential in the plane-wave state of a pseudospin-1/2 BEC with Rashba spin-orbit coupling [13]. In the reported experiment [14], the vortex dipoles have been nucleated by causing a highly oblate BEC to move past a repulsive Gaussian obstacle, and the critical velocity for vortex dipole shedding has been measured.…”

Vortex Dipole Excitations in Trapped Bose-Einstein Condensate.

“…In the mean-field framework, the dynamics of a system with N weakly identical atoms close to thermo-dynamic equilibrium and subject to weak dissipation can be described by the dissipative Gross-pitaevskii(GP) equation [15]: ISSN: 2320-5407 Int. J. Adv.…”