Non-Hermitian Acoustic Metamaterials: the role of Exceptional Points in sound absorption

Abstract

Effective non-Hermitian Hamiltonians are obtained to describe coherent perfect absorbing and lasing boundary conditions. PT -symmetry of the Hamiltonians enables to design configurations which perfectly absorb at multiple frequencies. Broadened and flat perfect absorption is predicted at the exceptional point of PT -symmetry breaking while, for a particular case, absorption is enhanced with the use of gain. The aforementioned phenomena are illustrated for acoustic scattering through Helmholtz resonators revealing how tailoring the non-Hermiticity of acoustic metamaterials leads to novel mechanisms for enhanced absorption.

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Cited by in corpus (36)

• Anatomy of skin modes and topology in non-Hermitian systems
• Optimal Sound Absorbing Structures
• Theory of reflectionless scattering modes
• Parametric amplification and bidirectional invisibility in PT-symmetric time-Floquet systems
• Meta-Programmable Analog Differentiator
• Experimental demonstration of asymmetric diffraction based on a passive parity-time-symmetric acoustic grating
• Anomalous energy transport in laminates with exceptional points
• Exceptional points in the thermoacoustic spectrum
• Stabilization of acoustic modes using Helmholtz and Quarter-Wave resonators tuned at exceptional points
• Scattering under Linear Non Self-Adjoint Operators: Case of in-Plane Elastic Waves
• Angular-asymmetric transmitting metasurface and splitter for acoustic wave: a combining of the Coherent Perfect Absorber and Laser
• Non-adiabatic transitions through exceptional points in the band structure of a PT-symmetric lattice
• Linking scalar elastodynamics and non-Hermitian quantum mechanics
• Duality of Topological Edge States in a Mechanical Kitaev Chain
• Strain topological metamaterials
• Exceptional points as signatures of dynamical magnetic phase transitions
• Acoustic Bound States in the Continuum in Coupled Helmholtz Resonators
• Virtual exceptional points in an electromechanical system
• Universal Route for the Emergence of Exceptional Points in PT-Symmetric Metamaterials with Unfolding Spectral Symmetries
• A high order continuation method to locate exceptional points and to compute Puiseux series with applications to acoustic waveguides
• Exceptional points and scattering of discrete mechanical metamaterials
• Rotation-time symmetry in bosonic systems and the existence of exceptional points in the absence of $\mathcal{P}\mathcal{T}$ symmetry
• Absorption characteristics of large acoustic metasurfaces
• Complete absorption of topologically protected waves
• Emergence of Exceptional Points in Periodic Metastructures with Hidden PT-symmetric Defects
• Exceptional points in single open acoustic resonator due to the symmetry breaking
• Generalized causality constraint based on duality symmetry reveals untapped potential of sound absorption
• Symmetry-driven Phononic Metamaterials
• Exceptional points in cylindrical elastic media with radiation loss
• Oblique scattering from non-Hermitian optical waveguides
• High-Order Perfect Absorption in the Absence of Exceptional Point
• Electromagnetic Eigenvalue Problems and Nonhermitian Effects in Linear and Saturable Scattering
• Regular sloshing modes in irregular cavities using metabathymetry
• In-Plane Linear Stress Waves in Layered Media: I. Non-Hermitian Degeneracies and Modal Chirality
• Acoustic scattering singularities via quasi-Bound states in the continuum
• Microwave and Acoustic Absorption Metamaterials