Gauge-spin-space rotation invariant vortices in spin-orbit coupled Bose-Einstein condensates
Gauge-spin-space rotation invariant vortices in spin-orbit coupled Bose-Einstein condensates
复制标题
DOI：
10.1103/physreva.88.013621
复制
发表时间：
2013-04
影响因子：
2.9
通讯作者：
Zhi-Fang Xu;S. Kobayashi;Masahito Ueda
中科院分区：
文献类型：
--
作者：
Zhi-Fang Xu;S. Kobayashi;Masahito Ueda
我们重新审视了具有Rashba自旋轨道耦合的旋量玻色-爱因斯坦凝聚的基态，并发现涡出现作为自发对称性破缺成组合规范，自旋和空间旋转对称性的直接后果，这决定了旋转中心的涡核自旋状态。对于连续的组合对称性，围绕旋转轴的总自旋旋转被限制为$2\pi$，而对于离散的组合对称性，我们进一步需要2F量子数来表征自旋-$F$系统的总自旋旋转。对于晶格相，我们发现，在基态的拓扑电荷为每个单元格消失。然而，我们在基于对称性分类的自旋-$\frac{1}{2}$系统中发现了两类具有非平凡拓扑荷的高度对称晶格，并表明它们是skyrmion晶体。
We revisit ground states of spinor Bose-Einstein condensates with a Rashba spin-orbit coupling, and find that votices show up as a direct consequence of spontaneous symmetry breaking into a combined gauge, spin, and space rotation symmetry, which determines the vortex-core spin state at the rotating center. For the continuous combined symmetry, the total spin rotation about the rotating axis is restricted to $2\pi$, whereas for the discrete combined symmetry, we further need 2F quantum numbers to characterize the total spin rotation for the spin-$F$ system. For lattice phases we find that in the ground state the topological charge for each unit cell vanishes. However, we find two types of highly symmetric lattices with a nontrivial topological charge in the spin-$\frac{1}{2}$ system based on the symmetry classification, and show that they are skyrmion crystals.