Elastic Waves in Curved Space: Mimicking a Wormhole

Zhu, Jian; Liu, Yongquan; Liang, Zixian; Chen, Tianning; Li, Jensen

doi:10.1103/physrevlett.121.234301

Cited by 65 publications

(34 citation statements)

References 43 publications

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“…Extensive previous research has determined that perfect sound absorption can be realized by the plate and membrane structures most similar to shells. Therefore, to fully extend the application range of shell-type structures 45 , in this section we hope to achieve perfect sound absorption through the shell-type structure. Previous work has shown that, by increasing the thickness of the air layer between the plate layers, a bilayer plate-type structure is able to achieve perfect sound absorption.…”

Section: Bilayer Shell-type Structure For Perfect Sound Absorptionmentioning

confidence: 99%

Shell-type acoustic metasurface and arc-shape carpet cloak

2019

Sci Rep

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We systematically propose a thin shell-type acoustic metasurface, which could be used to design a carpet cloak that closely covers an arc-shaped object, therefore providing the necessary support for hiding an object with any arbitrary shape. To facilitate the experimental measurement, however, the work here starts with some rotary spherical shell-type and ellipsoidal shell-type cell structures. The measured and calculated sound transmission loss (STL) results of these structures suggest that the sound insulation performances of the shell-type structure are quite different from those of the plate-type structure, indicating a possible break in the shape of the classical sound insulation curve. Considering also that cylindrical shell structures are more widely used in practice than the rotary shell structures, a number of two-dimensional bilayer cylindrical and elliptic cylindrical shell structures were, therefore, designed in this assay. Due to the asymmetry of the structure, the shell-type cells could exhibit bianisotropic sound absorption, reflection and effective parameters. Furthermore, the stiffness of the thin shell structure changed nonlinearly with the changing of the radius of curvature, with a wing shape tendency. In addition, a bilayer cylindrical shell-type acoustic metasurface and an arc-shaped carpet acoustic cloak were successively designed, wherein the phased compensation of differently shaped cell structures could be adjusted by means of a new engineering iso-phase design method. This work could provide the necessary guidance to extend existing results in the field of membrane- and plate-type acoustic metamaterials for shell-type structures, and the realization of the arc-shaped cloak could provide support for the design of a carpet acoustical cloak for use with arbitrary shapes.

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Section: Bilayer Shell-type Structure For Perfect Sound Absorptionmentioning

confidence: 99%

Shell-type acoustic metasurface and arc-shape carpet cloak

2019

Sci Rep

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“…Transformation optics actually has not been limited to the design of invisibility cloaks but has led to the development of novel wave‐manipulation devices. [ 37,40–42 ] Among them, the waveshifter, the building‐block of fundamental steering optical components such as the wave splitter, and the rotator, a device capable of twisting and restoring waves, creating at the same time a mirage effect, [ 43 ] have been proposed to control electromagnetic waves, [ 41 ] as well as scalar acoustic waves, [ 44,45 ] water waves, [ 46,47 ] or hydrodynamic flows. [ 48 ] Surprisingly, these new classes of devices have never been considered for elastic waves.…”

Section: Introductionmentioning

confidence: 99%

Pulse Dynamics of Flexural Waves in Transformed Plates

Tang

Guenneau

et al. 2021

Adv Funct Materials

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Coordinate‐transformation‐inspired optical devices have been mostly examined in the continuous‐wave regime: the performance of an invisibility cloak, which has been demonstrated for monochromatic excitation, is likely to deteriorate for short pulses. Here, pulse dynamics of flexural waves propagating in transformed plates is investigated. A practical realization of a waveshifter and a rotator for flexural waves based on the coordinate transformation method is proposed. Time‐resolved measurements reveal how the waveshifter deviates a short pulse from its initial trajectory, with no reflection at the bend and no spatial and temporal distortion of the pulse. Extending the strategy to cylindrical coordinates, a wave rotator is designed. It is demonstrated experimentally how a pulsed plane wave is twisted inside the rotator, while its wavefront is recovered behind the rotator and the pulse shape is preserved, with no extra time delay. The realization of the dynamical mirage effect is proposed, where an obstacle appears oriented in a deceptive direction.

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“…In addition, interesting phenomena such as wormholes [36], metric transitions [37,38], cosmological redshift [39], Einstein rings [40], Rindler space [41],uniform gravitational fields [42], and cosmic strings [43] were also observed. Recently, optical structures such as curved waveguides [44][45][46][47], nonlocal media [5,48], and optical lattices [49,50] have also been used to simulate these cosmic phenomena. One of the limitations of metamaterials that restricts us from exploring more complicated cases in gravitational fields is the demand for tremendous change in the refractive index, which requires a high level of material fabrication.…”

Section: Introductionmentioning

confidence: 99%

“…One of the limitations of metamaterials that restricts us from exploring more complicated cases in gravitational fields is the demand for tremendous change in the refractive index, which requires a high level of material fabrication. To overcome this difficulty, physicists have turned to the use of two-dimensional (2D) embedded curved surfaces to mimic gravitational fields [44][45][46][47]. Such a method expands the experimental platform of analog gravity.…”

Section: Introductionmentioning

confidence: 99%

Simulation of giant tidal force of wormhole using curved optical spaces

Liang

Zhu

et al. 2020

Phys. Rev. Research

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The tidal force of gravity is usually a weak force and is considered only in the movement of celestial bodies. However, in the presence of a very strong gravitational field, such as that of black holes and wormholes, tidal force also has an effect on light wave packets. In this work, we employ a curved optical waveguide to mimic the giant tidal force of wormholes on optical beams. We calculate the beam spreading caused by tidal force using general relativity. The theoretical calculations were in agreement with the experimental results. Our results show that the giant tidal force induces the divergence of optical deflection at the throat of a wormhole. This experimental system promises to be an effective methodology for the future studies mimicking gravitation.

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Elastic Waves in Curved Space: Mimicking a Wormhole

Cited by 65 publications

References 43 publications

Shell-type acoustic metasurface and arc-shape carpet cloak

Shell-type acoustic metasurface and arc-shape carpet cloak

Pulse Dynamics of Flexural Waves in Transformed Plates

Simulation of giant tidal force of wormhole using curved optical spaces

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