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arXiv · 1701.07618

PT-symmetric scattering in flow duct acoustics

Yves Aurégan·Vincent Pagneux
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Abstract

We show theoretically and experimentally that the propagation of an acoustic wave in an airflow duct going through a pair of diaphragms, with equivalent amount of mean-flow-induced effective gain and loss, displays all the features of a parity-time (PT) symmetric system. Using a scattering matrix formalism, we observe experimentally the properties which reflect the PT-symmetry of the scattering acoustical system: the existence of a spontaneous symmetry breaking with symmetry-broken pairs of scattering eigenstates showing amplification and reduction, and the existence of points with unidirectional invisibility.

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Yves Aurégan, Vincent Pagneux. 2017-01-26. PT-symmetric scattering in flow duct acoustics. https://doi.org/10.1103/physrevlett.118.174301

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