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Main Authors: Ammari, Habib, Hiltunen, Erik Orvehed, Liu, Ping, Miao, Borui, Zhu, Yi
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.05370
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author Ammari, Habib
Hiltunen, Erik Orvehed
Liu, Ping
Miao, Borui
Zhu, Yi
author_facet Ammari, Habib
Hiltunen, Erik Orvehed
Liu, Ping
Miao, Borui
Zhu, Yi
contents In this paper, we develop an accurate and efficient framework for computing subwavelength guided modes in high-contrast periodic media with line defects, based on a tight-binding approximation. The physical problem is formulated as an eigenvalue problem for the Helmholtz equation with high-contrast parameters. By employing layer potential theory on unbounded domains, we characterize the subwavelength frequencies via the quasi-periodic capacitance matrix. Our main contribution is the proof of exponential decay of the off-diagonal elements of the associated full and quasi-periodic capacitance matrices. These decay properties provide error bounds for the banded approximation of the capacitance matrices, thereby enabling a tight-binding approach for computing the spectral properties of subwavelength resonators with non-compact defects. Various numerical experiments are presented to validate the theoretical results, including applications to topological interface modes.
format Preprint
id arxiv_https___arxiv_org_abs_2512_05370
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Tight-binding Approach for Computing Subwavelength Guided Modes in Crystals with Line Defects
Ammari, Habib
Hiltunen, Erik Orvehed
Liu, Ping
Miao, Borui
Zhu, Yi
Mathematical Physics
65N25, 35B34, 35C20 35J05, 65N38
In this paper, we develop an accurate and efficient framework for computing subwavelength guided modes in high-contrast periodic media with line defects, based on a tight-binding approximation. The physical problem is formulated as an eigenvalue problem for the Helmholtz equation with high-contrast parameters. By employing layer potential theory on unbounded domains, we characterize the subwavelength frequencies via the quasi-periodic capacitance matrix. Our main contribution is the proof of exponential decay of the off-diagonal elements of the associated full and quasi-periodic capacitance matrices. These decay properties provide error bounds for the banded approximation of the capacitance matrices, thereby enabling a tight-binding approach for computing the spectral properties of subwavelength resonators with non-compact defects. Various numerical experiments are presented to validate the theoretical results, including applications to topological interface modes.
title A Tight-binding Approach for Computing Subwavelength Guided Modes in Crystals with Line Defects
topic Mathematical Physics
65N25, 35B34, 35C20 35J05, 65N38
url https://arxiv.org/abs/2512.05370