Observation of Degenerate Zero-Energy Topological States at Disclinations in an Acoustic Lattice
Observation of Degenerate Zero-Energy Topological States at Disclinations in an Acoustic Lattice
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DOI：
10.1103/physrevlett.128.174301
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发表时间：
2022-04-26
影响因子：
8.6
通讯作者：
Jing, Yun
中科院分区：
文献类型：
--
作者：
Deng, Yuanchen;Benalcazar, Wladimir A.;Jing, Yun
在物质拓扑相的体边界对应的基础上，向错最近被用来捕获经典波动系统中分数量子化的态密度（DOS）。虽然这些分数态具有局域化的向错关联态？的核心，这样的国家不受保护，从解除禁闭由于破坏手征对称性，一般导致共振，即使在原则上，有有限的寿命和次优的限制。在这里，我们设计和实验验证声学晶格的一个范例，拓扑状态绑定到向错没有分数DOS，但保持手征对称性。手征对称性的保持将态钉扎在中间带隙处，导致它们受到保护的最大限制。在缺陷处的整数DOS导致双重简并状态，由于对称性约束，不间隙。我们的研究提供了一个新的视角，在拓扑相位和拓扑缺陷的对称性保护之间的相互作用，在经典和量子系统的可能应用。
Building upon the bulk-boundary correspondence in topological phases of matter, disclinations have recently been harnessed to trap fractionally quantized density of states (DOS) in classical wave systems. While these fractional DOS have associated states localized to the disclination???s core, such states are not protected from deconfinement due to the breaking of chiral symmetry, generally leading to resonances which, even in principle, have finite lifetimes and suboptimal confinement. Here, we devise and experimentally validate in acoustic lattices a paradigm by which topological states bind to disclinations without a fractional DOS but which preserve chiral symmetry. The preservation of chiral symmetry pins the states at the midgap, resulting in their protected maximal confinement. The integer DOS at the defect results in twofold degenerate states that, due to symmetry constraints, do not gap out. Our study provides a fresh perspective about the interplay between symmetry protection in topological phases and topological defects, with possible applications in classical and quantum systems alike.