Synthetic gauge fields and Weyl point in Time-Reversal Invariant Acoustic Systems

By M. Xiao, Wen-Jie Chen, Wen-Yu He, Z. Zhang, C. T. Chan. 2015

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Inspired by the discovery of quantum hall effect 1-3 and topological insulator 4-8 , topological properties of classical waves start to draw worldwide attention 9-24 . Topological non-trivial bands characterized by non-zero Chern numbers are realized with external magnetic field induced time reversal symmetry breaking 10, 11, 23, 25 or dynamic modulation 12, 13 . Due to the absence of Faraday-like effect, the breaking of time reversal symmetry in an acoustic system is commonly realized with moving background fluids 19, 26 , and hence drastically increases the engineering complexity. Here we show that we can realize effective inversion symmetry breaking and effective gauge field in a reduced two-dimensional system by structurally engineering interlayer couplings, achieving an acoustic analog of the topological Haldane model 3, 27 . We then find and demonstrate unidirectional backscattering immune edge states. We show that the synthetic gauge field is closely related to the Weyl points 28-30 in the three-dimensional band structure.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/10c56d72e3f916d00daa6d91d030f904cadd5e1f