非厄米拓扑欧拉绝缘体
Non-Hermitian topological Euler insulators
AI总结：
本研究将拓扑欧拉绝缘体概念扩展至非厄米系统，提出理论框架，构建三类模型并揭示其独特拓扑特性，拓宽了非厄米开放系统中拓扑物质的范畴。
AI中文摘要：
拓扑欧拉绝缘体出现在具有实布洛赫哈密顿量和波函数的多带系统中，其脆弱拓扑由简并带的欧拉类表征，受二维中的PT或C₂T对称性保护，超出了拓扑物质的十重K理论分类。本研究将拓扑欧拉绝缘体的概念扩展到非厄米系统，提出理论框架以解锁其非平凡欧拉拓扑。针对二维三带对称哈密顿量非厄米晶格模型，系统描述其拓扑欧拉带、纠缠谱及体边对应关系，构建并研究三种典型非厄米欧拉绝缘体模型以阐释理论，进一步识别出非厄米起源的独特拓扑相变与反常边带重叠。本研究确立了非厄米系统中拓扑欧拉带的存在，揭示其有趣物理特性，拓宽了非厄米开放系统中拓扑物质的现有范畴。
英文摘要：
Topological Euler insulators emerge in multiband systems with real Bloch Hamiltonians and wavefunctions. Their fragile topologies are characterized by the Euler class of degenerate bands and protected by the $PT$ or $C_2T$ symmetry in two dimensions, which go beyond the tenfold $K$-theory classification of topological matter. In this work, we extend the conception of topological Euler insulators to non-Hermitian systems and propose a theoretical framework to unlock their nontrivial Euler topology. Focusing on two-dimensional, three-band non-Hermitian lattice models with symmetric Hamiltonians, we formulate a comprehensive description of their topological Euler bands, entanglement spectrum and bulk-boundary correspondence. Three typical models of non-Hermitian Euler insulators are constructed and investigated explicitly to illustrate our theory. Unique topological phase transitions and anomalous edge-band overlaps with non-Hermitian origins are further identified. Our study establishes the presence of topological Euler bands in non-Hermitian systems and unveils their intriguing physical characteristics, thereby broadening the existing territory of topological matter in non-Hermitian open systems.
