Anomalous energy transport in laminates with exceptional points

Lustig, Ben; Elbaz, Guy; Muhafra, Alan; Gal, Shmuel

doi:10.1016/j.jmps.2019.103719

Cited by 41 publications

(26 citation statements)

References 71 publications

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“…Despite the huge difference in the length scale that the two theories were developed for, fascinating realizations of quantum phenomena were demonstrated using macroscopic systems in recent years [2]. Examples include the Hall effect [3,4], geometric phase [5], and negative refraction [6][7][8][9][10]. Special attention is given to extraordinary transport properties based on PT symmetry [11][12][13][14][15][16][17][18], which corresponds to the commutativity of an operator with combined parity-time reversal operators.…”

Section: Introductionmentioning

confidence: 99%

Linking Scalar Elastodynamics and Non-Hermitian Quantum Mechanics

Gal¹,

Moiseyev²

2020

Phys. Rev. Applied

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Recent years have seen a fascinating pollination of ideas from quantum theories to elastodynamics-a theory that phenomenologically describes the time-dependent macroscopic response of materials.Here, we open route to transfer additional tools from non-Hermitian quantum mechanics. We begin by identifying the differences and similarities between the one-dimensional elastodynamics equation and the time-independent Schrödinger equation, and finding the condition under which the two are equivalent. Subsequently, we demonstrate the application of the non-Hermitian perturbation theory to determine the response of elastic systems; calculation of leaky modes and energy decay rate in heterogenous solids with open boundaries using a quantum mechanics approach; and construction of degeneracies in the spectrum of these assemblies. The latter result is of technological importance, as it introduces an approach to harness extraordinary wave phenomena associated with non-Hermitian degeneracies for practical devices, by designing them in simple elastic systems. As an example of such application, we demonstrate how an assembly of elastic slabs that is designed with two degenerate shear states according to our scheme, can be used for mass sensing with enhanced sensitivity by exploiting the unique topology near the exceptional point of degeneracy. arXiv:1910.07306v2 [cond-mat.soft]

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Section: Introductionmentioning

confidence: 99%

Linking Scalar Elastodynamics and Non-Hermitian Quantum Mechanics

Gal¹,

Moiseyev²

2020

Phys. Rev. Applied

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“…When considering the dynamical behavior of mechanical metamaterials, things become, if possible, even more impressive, given the unusual responses that such metamaterials can provide when coming in contact with elastic waves (Deymier, 2013;Hussein et al, 2014;Barchiesi et al, 2019). It is today possible to find researchers working on metamaterials exhibiting band-gaps (Liu et al, 2000;Wang et al, 2014;Zhu et al, 2015;Bilal et al, 2018;El Sherbiny and Placidi, 2018;Celli et al, 2019;Goh and Kallivokas, 2019;Koutsianitis et al, 2019), cloaking (Norris et al, 2014;Bückmann et al, 2015;Misseroni et al, 2016;Misseroni et al, 2019), focusing (Guenneau et al, 2007;Cummer et al, 2016), channelling (Kaina et al, 2017;Tallarico et al, 2017;Wang et al, 2018;Bordiga et al, 2019;Miniaci et al, 2019), negative refraction (Zhu et al, 2015;Srivastava, 2016;Willis, 2016;Bordiga et al, 2019;Lustig et al, 2019;Morini et al, 2019), etc., as soon as they interact with mechanical waves.…”

Section: Introductionmentioning

confidence: 99%

Exploring Metamaterials’ Structures Through the Relaxed Micromorphic Model: Switching an Acoustic Screen Into an Acoustic Absorber

et al. 2021

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While the design of always new metamaterials with exotic static and dynamic properties is attracting deep attention in the last decades, little effort is made to explore their interactions with other materials. This prevents the conception of (meta-)structures that can enhance metamaterials’ unusual behaviors and that can be employed in real engineering applications. In this paper, we give a first answer to this challenging problem by showing that the relaxed micromorphic model with zero static characteristic length can be usefully applied to describe the refractive properties of simple meta-structures for extended frequency ranges and for any direction of propagation of the incident wave. Thanks to the simplified model’s structure, we are able to efficiently explore different configurations and to show that a given meta-structure can drastically change its overall refractive behavior when varying the elastic properties of specific meta-structural elements. In some cases, changing the stiffness of a homogeneous material which is in contact with a metamaterial’s slab, reverses the structure’s refractive behavior by switching it from an acoustic screen (total reflection) into an acoustic absorber (total transmission). The present paper clearly indicates that, while the study and enhancement of the intrinsic metamaterials’ properties is certainly of great importance, it is even more challenging to enable the conception of meta-structures that can eventually boost the use of metamaterials in real-case applications.

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“…Fortunately, similar methods (Willis, 2016;Srivastava, 2016), which are also called mode-coupling methods for consistency, had been used in elastic waves to study negative refraction of anti-plane shear waves at a plane interface between a homogeneous elastic half-space and a layered periodic composite. Recently, these methods (Lustig et al, 2019;Lustig and Shmuel (2018); Mokhtari et al, 2019;Mokhtari et al, 2020) had been extended to study the scattering of in-plane elastic waves.…”

Section: Introductionmentioning

confidence: 99%

Flexural wave absorption by lossy gradient elastic metasurface

Cao

Yang

et al. 2020

Journal of the Mechanics and Physics of Solids

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In this research, we systematically study the flexural waves diffraction. Based on the diffraction mechanism, we propose the concept of subwavelength lossy gradient elastic metasurface for flexural waves absorption. We theoretically reveal that the highefficiency absorption behavior stems from maximum multireflection-enhanced absorption of 0 th order diffraction, and experimentally show that robust flexural wave quasi-omnidirectional absorption in the frequency range extending approximately from 340 Hz to 1000 Hz (larger than 1.5 octaves). In addition, we propose a general approach which involves new physics of adjusting the arrangement sequence of subunits to suppress the 1 st diffraction mode, to further reduce the sub-wavelength thickness of the metasurface while maintaining its high-efficiency absorption. Our designs could provide new routes to broadband vibration suppression and cancellation in lowfrequency by lossy elastic metamaterials and metasurfaces.

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Anomalous energy transport in laminates with exceptional points

Cited by 41 publications

References 71 publications

Linking Scalar Elastodynamics and Non-Hermitian Quantum Mechanics

Linking Scalar Elastodynamics and Non-Hermitian Quantum Mechanics

Exploring Metamaterials’ Structures Through the Relaxed Micromorphic Model: Switching an Acoustic Screen Into an Acoustic Absorber

Flexural wave absorption by lossy gradient elastic metasurface

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