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arXiv · 2110.08789

Observation of Non-Abelian Thouless Pump

Oubo You·Shanjun Liang·Biye Xie·Wenlong Gao·Weimin Ye·Jie Zhu·Shuang Zhang
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Abstract

Thouless pump is a one-dimensional dynamic topological effect that stems from the same topological mechanism as the renowned two-dimensional Chern insulators, with one momentum dimension replaced by a time variant evolution parameter. The underlying physics is abelian, concerning topologies of individual bands. By introducing multi-band non-abelian topology into pumping, much richer physics is expected that goes beyond the abelian counterpart. Here we report the observation of a non-abelian Thouless pump in an acoustic waveguide array with judiciously engineered coupling configurations. The observed non-abelian effect originates from time-evolution of eigen-states in Z_3 pump cycles that traverse across several band degeneracies in the parameter space in a three-band system. Interestingly, the pump of the eigenstates exhibits non-commutativity, i.e. the final state depends critically on the order of the pumping paths. Our study paves ways for exploring and utilizing non-abelian dynamical effects in classical systems.

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Oubo You, Shanjun Liang, Biye Xie, Wenlong Gao, Weimin Ye, Jie Zhu, Shuang Zhang. 2021-10-17. Observation of Non-Abelian Thouless Pump. https://doi.org/10.1103/physrevlett.128.244302

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