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Research Area

Author

  • Tetsu Magariyachi, Helena Arias Casals*, Ramon Herrero*, Muriel Botey*,Kestutis Staliunas*
  • * External authors

Company

  • Sony Corporation

Venue

  • PHYSICAL REVIEW

Date

  • 2021

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PT-symmetric Helmholtz resonator dipoles for sound directivity

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Abstract

Parity-time (PT)-symmetric or, more generally, non-Hermitian systems have opened a new area for unconventional management of waves, with significant applications, especially in optics. However, fewer proposals are found in acoustics, possibly due to the lack of a simple mechanism for coherent gain. In this paper, we propose a composite non-Hermitian system in acoustics consisting of assemblies of PT-symmetric Helmholtz resonator (HR) dipoles. Like meta-atoms are used as building elements in metamaterials, we propose PT-symmetric dipoles to design non-Hermitian systems intended to engineer complicated directivity fields. We theoretically analyze, numerically confirm, and experimentally show the symmetry breaking in a two-dimensional space of non-Hermitian dipoles consisting of a pair of Helmholtz resonators with different levels of gain and loss. In particular, we explore, as an application, a metastructure to concentrate the sound pressure inside the circular array formed by PT-symmetric dipoles. The proposed HR dipoles may be a convenient composite element for smart control of sound.

PHYSICAL REVIEW B

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