论文标题
铰链弧，费米弧和晶体对称性保护的纠缠签名
Entanglement Signature of Hinge Arcs, Fermi Arcs, and Crystalline Symmetry Protection in Higher-Order Weyl Semimetals
论文作者
论文摘要
纠缠频谱中的$ 1/2 $模式的存在已被证明是物质上差拓扑阶段的边界状态的强大量子信息，例如，拓扑绝缘器和拓扑超导体，有限的散装间隙使我们能够在其中建立$ 1/2 $ $ $ $ $ $ $ $ $的状态之间的晶体相应。在这里，我们研究了最近提出的高阶Weyl半法（HOWSM），其中大量支持无间隙的高阶Weyl节点，边界支持铰链弧和Fermi Arcs。我们发现，明确识别高阶边界状态的目的最终驱使我们充分利用特征纠缠的hamiltonian：ES和schmidt向量（纠缠波浪函数，abbr。EWF）。我们证明，尽管铰链弧和费米弧都贡献了$ 1/2 $模式，但与铰链弧和费米弧相对应的EWFS分别位于分区的虚拟铰链和表面上。此外，通过各种破坏对称的分区，我们可以确定保护边界状态的最小晶体对称性。因此，对于无间隙拓扑阶段，例如HOWSM，我们可以将ES和EWF结合起来，以普遍识别边界状态和潜在的对称要求。尽管howsm是无间隙阶段的典型实例，但我们的工作阐明了物质无间隙拓扑阶段的纠缠签名一般理论。
The existence of $1/2$ modes in the entanglement spectrum (ES) has been shown to be a powerful quantum-informative signature of boundary states of gapped topological phases of matter, e.g., topological insulators and topological superconductors, where the finite bulk gap allows us to establish a crystal-clear correspondence between $1/2$ modes and boundary states. Here we investigate the recently proposed higher-order Weyl semimetals (HOWSM), where bulk supports gapless higher-order Weyl nodes and boundary supports hinge arcs and Fermi arcs. We find that the aim of unambiguously identifying higher-order boundary states ultimately drives us to make full use of eigen quantities of the entanglement Hamiltonian: ES as well as Schmidt vectors (entanglement wavefunctions, abbr. EWF). We demonstrate that, while both hinge arcs and Fermi arcs contribute to $1/2$ modes, the EWFs corresponding to hinge arcs and Fermi arcs are respectively localized on the virtual hinges and surfaces of the partition. Besides, by means of various symmetry-breaking partitions, we can identify the minimal crystalline symmetries that protect boundary states. Therefore, for gapless topological phases such as HOWSMs, we can combine ES and EWF to universally identify boundary states and potential symmetry requirement. While HOWSMs are prototypical examples of gapless phases, our work sheds light on general theory of entanglement signature in gapless topological phases of matter.
