Multiple scattering theory of non-Hermitian sonic second-order topological insulators
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Abstract Topological phases of sound enable unconventional confinement of acoustic energy at the corners in higher-order topological insulators. These unique states which go beyond the conventional bulk-boundary correspondence have recently been extended to non-Hermitian wave physics comprising finite crystal structures including loss and gain units. We use a multiple scattering theory to calculate these topologically trapped complex states that agree very well to finite element predictions. Moreover, our semi-numerical tool allows us to compute the spectral dependence of corner states in the presence of defects, illustrating the limits of the topological resilience of these confined non-Hermitian acoustic states.
Keyword(s):
2005 ◽
Vol 17
(25)
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pp. 3735-3757
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Keyword(s):
1991 ◽
Vol 78
(7)
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pp. 671-675
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