Universal route for the emergence of exceptional points in PT-symmetric metamaterials with unfolding spectral symmetries
Universal route for the emergence of exceptional points in PT-symmetric metamaterials with unfolding spectral symmetries
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DOI：
10.1088/1367-2630/ac09c9
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发表时间：
2020-08
影响因子：
3.3
通讯作者：
Yanghao Fang;T. Kottos;R. Thevamaran
中科院分区：
文献类型：
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作者：
Yanghao Fang;T. Kottos;R. Thevamaran
我们介绍了一类奇偶时对称弹性动力超材料（Ed-MetaMater），其厄米对应物表现出展开（分形）谱对称性。我们的研究揭示了这些ed - metamers中异常点的无标度形成，其密度由其厄米谱的分形维数决定。我们利用有限元模型证明了准周期Aubry-Harper Ed-MetaMater、几何H-tree-fractal Ed-MetaMater和非周期Fibonacci Ed-MetaMater中具有特定分形谱的无标度ep -形成，并通过具有可控分形谱的耦合模式理论模型建立了ep -形成的通用路径。这种通用性可以合理设计用于超灵敏传感和弹性波控制的新型Ed-MetaMater。
We introduce a class of parity-time symmetric elastodynamic metamaterials (Ed-MetaMater) whose Hermitian counterpart exhibits unfolding (fractal) spectral symmetries. Our study reveals a scale-free formation of exceptional points in those Ed-MetaMaters whose density is dictated by the fractal dimension of their Hermitian spectra. We demonstrate this scale-free EP-formation in a quasi-periodic Aubry-Harper Ed-MetaMater, a geometric H-tree-fractal Ed-MetaMater, and an aperiodic Fibonacci Ed-MetaMater—each having a specific fractal spectrum—using finite element models and establish a universal route for EP-formation via a coupled mode theory model with controllable fractal spectrum. This universality may enable the rational design of novel Ed-MetaMater for hypersensitive sensing and elastic wave control.