发表机构
Instituto de Física Teórica, Universidade Estadual Paulista（圣保罗州立大学理论物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过比较两种搅拌协议，研究偶极BEC中涡旋成核与动力学，发现偶极相互作用抑制涡旋衰变并产生三角排列，为量子湍流实验提供基准。
AI 中文摘要
我们研究了由旋转高斯障碍物搅拌的偶极玻色-爱因斯坦凝聚体中的涡旋成核与动力学。比较了两种搅拌协议：恒定振幅的连续搅拌（情形1），以及在$t = 15$ ms时通过线性振幅斜坡下降移除障碍物（情形2）。在两种情形下，平滑的角速度斜坡（$t_{\text{acc}} = 3$ ms）抑制了虚假的声子激发。第一对涡旋在$t \sim 3$ ms时离开障碍物，到$t \sim 8$ - $10$ ms时，单个涡旋和反涡旋在相位图中完全分辨。情形1产生的涡旋数量增长至$t \sim 40$ ms后大致饱和，而情形2产生的涡旋数量在$t \sim 15$ - $25$ ms左右达到峰值后减少。值得注意的是，两种协议在$t \sim 50$ ms时都在凝聚体的选定区域导致了局部的三角状排列，表现出清晰的偶极特征：沿极化轴的椭圆畸变和拉长的涡旋核心。混合的涡旋-反涡旋群体在高达$100$ ms的时间内保持稳定，没有观察到湮灭，表明偶极相互作用强烈抑制了涡旋衰变。动能分解证实，不可压缩（涡旋）能量在后期占主导。这些结果为偶极超流体中的涡旋研究建立了一个受控平台，并为未来关于具有长程各向异性相互作用的量子湍流的实验提供了基准。
英文摘要
We investigate vortex nucleation and dynamics in a dipolar Bose-Einstein condensate stirred by a rotating Gaussian obstacle. Two stirring protocols are compared: continuous stirring with constant amplitude (Case 1), and obstacle removal at $t = 15$ ms with linear amplitude ramp-down (Case 2). In both cases, a smooth angular velocity ramp ($t_{\text{acc}} = 3$ ms) suppresses spurious phonon excitations. The first vortex pairs exit the obstacle at $t \sim 3$ ms, and by $t \sim 8$ - $10$ ms the individual vortices and antivortices are fully resolved in the phase maps. Case 1 yields a vortex population that grows up to $t \sim 40$ ms and then roughly saturates, while Case 2 yields a population that peaks around $t \sim 15$ - $25$ ms and then decreases. Remarkably, both protocols lead to local triangular-like ordering in selected regions of the condensate by $t \sim 50$ ms, exhibiting clear dipolar signatures: elliptical distortion and elongated vortex cores along the polarization axis. The mixed vortex-antivortex population remains stable up to $100$ ms with no observable annihilation, indicating that dipolar interactions strongly suppress vortex decay. Kinetic energy decomposition confirms that incompressible (vortex) energy dominates at late times. These results establish a controlled platform for vortex studies in dipolar superfluids and provide benchmarks for future experiments on quantum turbulence with long-range anisotropic interactions.
Comments8 pages, 6 figures
