Experimental realization of non-Abelian topological bands

Abstract:

Topological phases of matter connect mathematical principles to real materials, and may shape future electronic and quantum technologies. So far, this discipline has mostly focused on single-gap topology described by topological invariants such as Chern numbers. Here, based on a tunable kagome model, we observe non-Abelian band topology and its transitions in acoustic semimetals and insulators, in which the multi-gap Hilbert space plays a key role. In non-Abelian semimetals, the topological charges of band nodes are converted through the braiding of nodes in adjacent gaps, and their behaviour cannot be captured by conventional topological band theory. By controlling the geometry of the acoustic metamaterials, topological transitions are induced by the creation, annihilation, merging and splitting of band nodes. This reveals the underlying rules for the conversion and transfer of non-Abelian topological charges in multiple bandgaps. The resulting laws that govern the evolution of band nodes in non-Abelian multi-gap systems should inspire studies on multi-band topological semimetals and multi-gap topological out-of-equilibrium systems.

Acknowledgement : This work was supported by the National Nature Science Foundation of China (12125504, 12074281) and Jiangsu specially-appointed professor funding.

Bio:

蒋建华，苏州大学教授。2000-2010年在中国科学技术大学学习，获学士和博士学位。之后在以色列魏茨曼研究所和加拿大多伦多大学从事博士后研究。2015年起任苏州大学教授，2021年获得国家杰出青年基金项目的资助。主要从事拓扑光子学/声子学、非平衡统计物理等方面的研究。拓展了利用室温光子和声子系统发现新颖拓扑物理效应的研究，特别在拓扑体-缺陷对应关系、高阶拓扑态、非阿贝尔拓扑态等方面做出了一系列享有国际声誉的工作，并在非平衡统计物理和非常规热电效应方面做了一系列基础性、开拓性的工作。发表同行评审学术论文100余篇（含Nature、Nature子刊、Phys. Rev. Lett.等）。曾获中国光学十大进展等奖项，并获得江苏特聘教授、教育部国家级青年人才等荣誉。2022年以首席科学家的身份获得科技部国家重点研发计划的支持。