利用受 $K$-理论启发的实验协议揭示金属中的拓扑
Revealing Topology in Metals using Experimental Protocols Inspired by $K$-Theory
AI总结：
本研究受K-理论启发，提出实验协议，在无带隙声学金属中直接观察拓扑现象，通过重新解释复合算子测量拓扑不变量，为无带隙材料拓扑发现提供通用方法。
摘要：
拓扑金属是具有无带隙能带结构和非平凡边缘局域共振的特殊导电材料，由于传统的拓扑分类方法在此情境下不适用，其发现一直难以实现。受近期理论发展的启发，这些发展利用了 $C^*$-代数领域的技术来识别拓扑金属 \n\cite{cerjan_local_2021}，在此，我们直接观察了无带隙声子晶体中的拓扑现象，并提供了一种通用的实验技术来证明其拓扑性。具体而言，我们不仅在拓扑声学金属中观察到了鲁棒的边界局域态，还将从问题的 $K$-理论中数学推导出的一个复合算子重新解释为新的哈密顿量，其物理实现使我们能够直接观察拓扑谱流并测量拓扑不变量。我们的观察和实验协议可能为在缺乏体带隙的广泛人工和天然材料中发现拓扑行为提供见解。
英文摘要：
Topological metals are special conducting materials with gapless band structures and nontrivial edge-localized resonances, whose discovery has proved elusive because the traditional topological classification methods do not apply in this context. Inspired by recent theoretical developments that leveraged techniques from the field of $C^*$-algebras to identify topological metals \cite{cerjan_local_2021}, here, we directly observe topological phenomena in gapless acoustic crystals and provide a general experimental technique to demonstrate their topology. Specifically, we not only observe robust boundary-localized states in a topological acoustic metal, but also re-interpret a composite operator, mathematically derived from the K-theory of the problem, as a new Hamiltonian, whose physical implementation allows us to directly observe a topological spectral flow and measure the topological invariants. Our observations and experimental protocols may offer insights for discovering topological behavior across a wide array of artificial and natural materials that lack bulk band gaps.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
