We study quantum vortex states consisting of a ring of vortices with alternating sign, in a homogeneous superfluid confined to a circular domain. We find an exact stationary solution of the point vortex model for the neutral vortex necklace. We investigate the stability of the necklace state within both the point-vortex model and the Gross–Pitaevskii equation describing a trapped atomic Bose–Einstein condensate at low temperature. The point-vortex stationary states are found to also be stationary states of the Gross–Pitaevskii equation provided the finite thickness of the outer fluid boundary is accounted for. Under significant perturbation, the Gross–Pitaevskii evolution and point-vortex model exhibit instability as expected for metastable states. The perturbed vortex necklace exhibits sensitivity to the perturbation, suggesting a route to seeding vortex chaos or quantum turbulence.

中文翻译：

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被困平面超流体中的中性涡流项链

我们研究了由具有交替符号的涡环组成的量子涡旋状态，在局限于圆形域的均匀超流体中。我们为中性涡旋项链找到了点涡模型的精确平稳解。我们在点涡模型和描述低温下被困原子玻色-爱因斯坦凝聚的 Gross-Pitaevskii 方程中研究了项链状态的稳定性。如果考虑到外部流体边界的有限厚度，则发现点涡流稳态也是 Gross-Pitaevskii 方程的稳态。在显着扰动下，Gross-Pitaevskii 演化和点涡模型表现出亚稳态所预期的不稳定性。扰动涡旋项链对扰动表现出敏感性，