六极子磁场中自旋轨道耦合玻色-爱因斯坦凝聚体的基态结构

研究囚禁在环形势中的Rashba自旋轨道耦合玻色-爱因斯坦凝聚体在六极子磁场中的基态特性。在这种情况下,磁场破坏了自旋轨道耦合哈密顿量的旋转对称性,但系统仍具有2π/3的离散对称性。数值结果发现:在弱相互作用情况下,六极子磁场和Rashba自旋轨道耦合使环形囚禁的凝聚体呈类六边形的基态密度分布,当磁场强度超过某一临界值时,凝聚体将崩塌;在强相互作用情况下,半量子涡旋出现在凝聚体中,且被六极子磁场钉在方位角Ф=nπ/3的径向位置,涡旋的旋转方向取决于径向磁场的方向。

Ground States of Spin-orbit Coupled Bose-Einstein Condensates in the Presence of Sextupole Magnetic Field

The ground states of Rashba spin-orbit coupled Bose-Einstein condensates are investigated in the presence of sextupole magnetic field.In this case,the rotational symmetry of the spin-orbit coupled Hamiltonian is broken by the sextupole magnetic field,but a discrete symmetry of 2π/3 maintains.Numerical results show that in the case of weak interaction,the hexagon-like structures appear in the ground-state condensates due to the coupling of the sextupole magnetic field and Rashba spin-orbit coupling,and when the magnetic field strength exceeds some critical value,the condensates collapse;in the case of strong interaction,half-quantum vortices appear in the condensates and are pinned by the sextupole magnetic field at the radial position with azimuth Ф=nπ/3(n being integer),and the winding direction of vortices depends on the direction of magnetic field.