论文标题
观察双曲线晶格中新型拓扑状态
Observation of novel topological states in hyperbolic lattices
论文作者
论文摘要
新型拓扑状态的发现已成为物理和材料科学领域的主要分支。但是,迄今为止,大多数已建立的物质拓扑状态已在欧几里得系统中使用,在欧几里得系统中,弯曲空间的独特几何特征与外来拓扑阶段之间的相互作用的探索较少,尤其是从实验性角度来看。最近,双曲线晶格的实验实现,这是具有恒定阴性曲率的非欧亚人空间中的常规镶嵌物,在模拟曲面空间中量子物理学的外来现象的领域引起了很多关注。问题是,在这种非欧几里得系统中是否存在新的拓扑状态,而在欧几里得空间中没有类似物。在这里,我们在理论和实验中都证明了具有独特特性的新型拓扑状态与其欧几里得对应物相比可以存在于工程双曲线晶格中。特别是,基于扩展的Haldane模型,实现了具有非平凡的真实空间Chern数字的边界主导的一阶Chern边缘状态,并证明了相关的单向传播。此外,我们表明类似分形的Midgap高阶零模式出现在变形双曲线晶格中,其中零模式的数量随着晶格尺寸的增加而成倍增加。通过测量位置分辨的强迫响应和电压数据包动力学,可以在设计的双曲电路网络中观察到这些新型的拓扑状态。我们的发现提出了一个新的平台,用于研究欧几里得空间以外的拓扑阶段,并可能在设计高效拓扑设备(例如拓扑激光器)的领域具有潜在的应用,该领域的琐碎区域较少。
The discovery of novel topological states has served as a major branch in physics and material science. However, to date, most of the established topological states of matter have been employed in Euclidean systems, where the interplay between unique geometrical characteristics of curved spaces and exotic topological phases is less explored, especially on the experimental perspective. Recently, the experimental realization of the hyperbolic lattice, which is the regular tessellation in non-Euclidean spaces with a constant negative curvature, has attracted much attention in the field of simulating exotic phenomena from quantum physics in curved spaces to the general relativity. The question is whether there are novel topological states in such a non-Euclidean system without analogues in Euclidean spaces. Here, we demonstrate both in theory and experiment that novel topological states possessing unique properties compared with their Euclidean counterparts can exist in engineered hyperbolic lattices. Specially, based on the extended Haldane model, the boundary-dominated first-order Chern edge state with a nontrivial real-space Chern number is achieved, and the associated one-way propagation is proven. Furthermore, we show that fractal-like midgap higher-order zero modes appear in deformed hyperbolic lattices, where the number of zero modes increases exponentially with the increase of lattice size. These novel topological states are observed in designed hyperbolic circuit networks by measuring site-resolved impendence responses and dynamics of voltage packets. Our findings suggest a novel platform to study topological phases beyond Euclidean space and may have potential applications in the field of designing high-efficient topological devices, such as topological lasers, with extremely fewer trivial regions.