Stability and internal structure of vortices in spin-1 Bose-Einstein condensates with conserved magnetization
Stability and internal structure of vortices in spin-1 Bose-Einstein condensates with conserved magnetization
复制标题
DOI：
10.1103/physreva.93.033633
复制
发表时间：
2016-03-18
影响因子：
2.9
通讯作者：
Ruostekoski, Janne
中科院分区：
文献类型：
--
作者：
Lovegrove, Justin;Borgh, Magnus O.;Ruostekoski, Janne
我们通过提供非奇异和奇异涡旋状态的系统表征，证明了纵向磁化守恒如何对原子自旋-1玻色-爱因斯坦凝聚体中涡旋的稳定性和结构产生显著影响。构建了连续连接铁磁相和极相的涡旋态的旋量波函数，系统地推导了不同奇异涡旋的非旋转磁芯和具有不同小距离和大距离拓扑结构的复合缺陷态的解析模型。我们解释了当印在凝聚体上的无芯涡旋在原子相互作用的极性区松弛时，守恒定律是如何提供稳定机制的。由此产生的结构形成复合缺陷：内部铁磁无芯涡旋向外部单量子化极涡旋变形。我们还用数值方法展示了其他更复杂的涡核拓扑结构是如何稳定的。此外，我们还分析了铁磁凝聚体中无芯涡旋的结构，并展示了降低磁化强度如何导致涡旋从陷阱中心位移，最终导致其核心变形和分裂，从而使单一涡旋变为低能态。对于奇异涡旋，我们发现其稳定性和核心结构受磁化守恒的影响较小。
We demonstrate how conservation of longitudinal magnetization can have pronounced effects on both stability and structure of vortices in the atomic spin-1 Bose-Einstein condensate by providing a systematic characterization of nonsingular and singular vortex states. Constructing spinor wave functions for vortex states that continuously connect ferromagnetic and polar phases, we systematically derive analytic models for nonrotating cores of different singular vortices and for composite defect states with distinct small- and large-distance topology. We explain how the conservation law provides a stabilizing mechanism when the coreless vortex imprinted on the condensate relaxes in the polar regime of interatomic interactions. The resulting structure forms a composite defect: The inner ferromagnetic coreless vortex deforms toward an outer singly quantized polar vortex. We also numerically show how other even more complex hierarchies of vortex-core topologies may be stabilized. Moreover, we analyze the structure of the coreless vortex also in a ferromagnetic condensate and show how reducing magnetization leads to a displacement of the vortex from the trap center and eventually to the deformation and splitting of its core where a singular vortex becomes a lower-energy state. For the case of singular vortices, we find that the stability and the core structure are notably less influenced by the conservation of magnetization.