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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Maksimov D. N., Sadreev A. F., Lyapina A. A., Pilipchuk A. S.
Заглавие : Coupled mode theory for acoustic resonators
Коллективы : Russian Science Foundation [14-12-00266]
Место публикации : Wave Motion: Elsevier Science, 2015. - Vol. 56. - P.52-66. - ISSN 0165, DOI 10.1016/j.wavemoti.2015.02.003. - ISSN 1878433X(eISSN)
Примечания : Cited References:42. - We thank K.N. Pichugin for helpful discussions. The work was supported by grant 14-12-00266 from Russian Science Foundation.
Предметные рубрики: WAVE-GUIDES
TRAPPED MODES
DISCONTINUITIES
TRANSMISSION
BILLIARDS
Ключевые слова (''Своб.индексиров.''): coupled mode theory--non-hermitian hamiltonian--acoustic resonator--s-matrix
Аннотация: We develop the effective non-Hermitian Hamiltonian approach for open systems with Neumann boundary conditions. The approach can be used for calculating the scattering matrix and the scattering function in open resonator–waveguide systems. In higher than one dimension the method represents acoustic coupled mode theory in which the scattering solution within an open resonator is found in the form of expansion over the eigenmodes of the closed resonator decoupled from the waveguides. The problem of finding the transmission spectra is reduced to solving a set of linear equations with a non-Hermitian matrix whose anti-Hermitian term accounts for coupling between the resonator eigenmodes and the scattering channels of the waveguides. Numerical applications to acoustic two-, and three-dimensional resonator–waveguide problems are considered.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nesterov A. I., Ovchinnikov S. G.
Заглавие : Geometric phases and quantum phase transitions in open systems
Место публикации : Phys. Rev. E: AMER PHYSICAL SOC, 2008. - Vol. 78, Is. 1. - Ст.15202. - ISSN 1539-3755, DOI 10.1103/PhysRevE.78.015202
Примечания : Cited References: 29
Предметные рубрики: POINTS
DEGENERACIES
Ключевые слова (''Своб.индексиров.''): chlorine compounds--electron tunneling--ferromagnetism--ising model--magnetic fields--magnetism--open systems--quantum electronics--quantum optics--sedimentation--effective hamiltonian--eigenvalues--first orders--geometric phase--geometric phases--ground-state--hermitian--one-dimensional--open quantum systems--quantum phase transition--quantum phase transitions--transverse-magnetic fields--phase transitions
Аннотация: The relationship is established between quantum phase transitions and complex geometric phases for open quantum systems governed by a non-Hermitian effective Hamiltonian with accidental crossing of the eigenvalues. In particular, the geometric phase associated with the ground state of the one-dimensional dissipative Ising model in a transverse magnetic field is evaluated, and it is demonstrated that the related quantum phase transition is of the first order.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pilipchuk A. S., Pilipchuk A. A., Sadreev A. F.
Заглавие : Bound states in the continuum in open spherical resonator
Место публикации : Phys. Scr. - 2020. - Vol. 95, Is. 8. - Ст.085002. - ISSN 00318949 (ISSN), DOI 10.1088/1402-4896/ab99fb
Примечания : Cited References: 33
Аннотация: We consider the bound states in the continuum (BICs) or embedded trapped modes in an open spherical acoustic resonator. The eigenfrequencies of closed resonator are 2l+1-fold degenerated, where l is the orbital index. An attachment of two cylindrical waveguides lifts this degeneracy and transforms the eigenfrequencies into resonances whose real parts depend on the position of the waveguides. When the waveguides are angled by θ ≠ π, variation over that angle gives rise to avoided crossings of resonant modes with different l to result in the Friedrich-Wintgen BICs. For θ = π there might be only the symmetry protected BICs. When three waveguides are connected to the spherical resonator the Friedrich-Wintgen BICs occur due to the avoided crossings of resonant modes with the same l but different azimuthal indices -l ≤ m ≤ l.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sadreev A. F.
Заглавие : Interference traps waves in an open system: bound states in the continuum
Коллективы : Russian Foundation for Basic Research Projects [19-02-00055]
Место публикации : Rep. Prog. Phys. - 2021. - Vol. 84, Is. 5. - Ст.055901. - ISSN 0034-4885, DOI 10.1088/1361-6633/abefb9. - ISSN 1361-6633(eISSN)
Примечания : Cited References: 154. - The work was partially supported by Russian Foundation for Basic Research Projects No. 19-02-00055
Предметные рубрики: FANO RESONANCES
2ND-HARMONIC GENERATION
QUANTUM-SYSTEMS
UNIFIED THEORY
Аннотация: I review the four mechanisms of bound states in the continuum (BICs) in the application of microwave and acoustic cavities open to directional waveguides. The most simple are symmetry-protected BICs, which are localized inside the cavity because of the orthogonality of the eigenmodes to the propagating modes of waveguides. However, the most general and interesting is the Friedrich-Wintgen mechanism, when the BICs are the result of the fully destructive interference of outgoing resonant modes. The third type of BICs, Fabry-Perot BICs, occurs in a double resonator system when each resonator can serve as an ideal mirror. Finally, the accidental BICs can be realized in the open cavities with no symmetry like the open Sinai billiard in which the eigenmode of the resonator can become orthogonal to the continuum of the waveguide accidentally due to a smooth deformation of the eigenmode. We also review the one-dimensional systems in which the BICs occur owing to the fully destructive interference of two waves separated by spin or polarization or by paths in the Aharonov-Bohm rings. We make broad use of the method of effective non-Hermitian Hamiltonian equivalent to the coupled mode theory, which detects BICs by finding zero-width resonances.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Huang L., Jia B., Pilipchuk A. S., Chiang Y., Huang S., Li J., Shen C., Bulgakov E. N., Deng F., Powell D. A., Cummer S. A., Li Y., Sadreev A. F., Miroshnichenko A. E.
Заглавие : General framework of bound states in the continuum in an open acoustic resonator
Место публикации : Phys. Rev. Appl. - 2022. - Vol. 18, Is. 5. - Ст.054021. - ISSN 23317019 (eISSN), DOI 10.1103/PhysRevApplied.18.054021
Примечания : Cited References: 47. - L.H. and A.E.M. are supported by the Australian Research Council Discovery Project (Grant No. DP200101353) and the UNSW Scientia Fellowship program. Y.K.C. and D.A.P. are supported by the Australian Research Council Discovery Project (Grant No. DP200101708). B.J., S.H., and Y.L. are supported by the National Natural Science Foundation of China (Grant No. 12074286) and the Shanghai Science and Technology Committee (Grant No. 21JC1405600). A.P., E.B., and A.S. are supported by the Russian Science Foundation (Grant No. 22-12-00070)
Аннотация: Bound states in the continuum (BICs) provide a viable way of achieving high-Q resonances in both photonics and acoustics. In this work, we propose a general method of constructing Friedrich-Wintgen (FW) BICs and accidental BICs in a coupled acoustic waveguide-resonator system. We demonstrate that FW BICs can be achieved with arbitrary two degenerate resonances in a closed resonator, regardless of whether they have the same or opposite parity. Moreover, their eigenmode profiles can be arbitrarily engineered by adjusting the position of the attached waveguide. This suggests an effective way of continuously switching the nature of the BICs from FW BICs to symmetry-protected BICs or accidental BICs. Also, such BICs are sustained in the coupled waveguide-resonator system with shapes such as rectangles, ellipses, and rhomboids. These interesting phenomena are well explained by the two-level effective non-Hermitian Hamiltonian, where two strongly coupled degenerate modes play a major role in forming such FW BICs. Additionally, we find that such an open system also supports accidental BICs in geometry space instead of momentum space via tuning the position of the attached waveguide, which is attributed to the quenched coupling between the waveguide and eigenmodes of the closed cavity. Finally, we fabricate a series of three-dimensional coupled resonator waveguides and experimentally verify the existence of FW BICs and accidental BICs by measuring the transmission spectra. Our results complement the current BIC library in acoustics and provide nice routes for designing acoustic devices, such as acoustic absorbers, filters, and sensors.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Huang, Lujun, Huang, Sibo, Shen, Chen, Yves, Simon, Pilipchuk A. S., Ni, Xiang, Kim, Seunghwi, Chiang, Yan Kei, Powell, David A., Zhu, Jie, Cheng, Ya, Li, Yong, Sadreev A. F., Alu, Andrea, Miroshnichenko, Andrey E.
Заглавие : Acoustic resonances in non-Hermitian open systems
Колич.характеристики :17 с
Место публикации : Nat. Rev. Phys. - 2024. - Vol. 6, Is. 1. - P.11-27. - ISSN 25225820 (eISSN), DOI 10.1038/s42254-023-00659-z
Примечания : Cited References: 288. - L.H. and A.E.M. were supported by the Australian Research Council Discovery Project (DP200101353) and the UNSW Scientia Fellowship programme. S.H. and Y.L. were supported by the Shanghai Science and Technology Committee (grant nos. 21JC1405600). C.S. was supported by the US National Science Foundation under grant no. CMMI-2137749. S.Y., X.N., S.K. and A.A. were supported by the Air Force Office of Scientific Research and Simons Foundation. A.S.P and A.F.S acknowledge the state assignment of Kirensky Institute of Physics. Y.K.C. and D.A.P. were supported by the Australian Research Council Discovery Project (grant no. DP200101708)
Аннотация: Acoustic resonances in open systems, which are usually associated with resonant modes characterized by complex eigenfrequencies, play a fundamental role in manipulating acoustic wave radiation and propagation. Notably, they are accompanied by considerable field enhancement, boosting interactions between waves and matter, and leading to various exciting applications. In the past two decades, acoustic metamaterials have enabled a high degree of control over tailoring acoustic resonances over a range of frequencies. Here, we provide an overview of recent advances in the area of acoustic resonances in non-Hermitian open systems, including Helmholtz resonators, metamaterials and metasurfaces, and discuss their applications in various acoustic devices, including sound absorbers, acoustic sources, vortex beam generation and imaging. We also discuss bound states in the continuum and their applications in boosting acoustic wave–matter interactions, active phononics and non-Hermitian acoustic resonances, including phononic topological insulators and the acoustic skin effect.
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