Optimal multipole center for subwavelength acoustic scatterers

Fuente: arXiv
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Autori principali: Ustimenko, Nikita, Rockstuhl, Carsten, Kildishev, Alexander V.
Natura: Preprint
Pubblicazione: 2025
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author Ustimenko, Nikita
Rockstuhl, Carsten
Kildishev, Alexander V.
author_facet Ustimenko, Nikita
Rockstuhl, Carsten
Kildishev, Alexander V.
contents The multipole expansion is a powerful framework for analyzing how subwavelength-size objects scatter waves in optics or acoustics. The calculation of multipole moments traditionally uses the scatterer's center of mass as the reference point. The theoretical foundation of this heuristic convention remains an open question. Here, we challenge this convention by demonstrating that a different, optimal multipole center can yield superior results. The optimal center is crucial -- it allows us to accurately express the scattering response while retaining a minimum number of multipole moments. Our analytical technique for finding the optimal multipole centers of individual scatterers, both in isolation and within finite arrays, is validated through numerical simulations. Our findings reveal that such an optimized positioning significantly reduces quadrupole contributions, enabling more accurate monopole-dipole approximations in acoustic calculations. Our approach also improves the computational efficiency of the T-matrix method, offering practical benefits for metamaterial design and analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2501_06168
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimal multipole center for subwavelength acoustic scatterers
Ustimenko, Nikita
Rockstuhl, Carsten
Kildishev, Alexander V.
Classical Physics
Applied Physics
Computational Physics
The multipole expansion is a powerful framework for analyzing how subwavelength-size objects scatter waves in optics or acoustics. The calculation of multipole moments traditionally uses the scatterer's center of mass as the reference point. The theoretical foundation of this heuristic convention remains an open question. Here, we challenge this convention by demonstrating that a different, optimal multipole center can yield superior results. The optimal center is crucial -- it allows us to accurately express the scattering response while retaining a minimum number of multipole moments. Our analytical technique for finding the optimal multipole centers of individual scatterers, both in isolation and within finite arrays, is validated through numerical simulations. Our findings reveal that such an optimized positioning significantly reduces quadrupole contributions, enabling more accurate monopole-dipole approximations in acoustic calculations. Our approach also improves the computational efficiency of the T-matrix method, offering practical benefits for metamaterial design and analysis.
title Optimal multipole center for subwavelength acoustic scatterers
topic Classical Physics
Applied Physics
Computational Physics
url https://arxiv.org/abs/2501.06168