Non-Hermitian impurity problem

Fuente: arXiv
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Auteurs principaux: Kokkinakis, E. T., Komis, I., Makris, K. G., Economou, E. N.
Format: Preprint
Publié: 2025
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author Kokkinakis, E. T.
Komis, I.
Makris, K. G.
Economou, E. N.
author_facet Kokkinakis, E. T.
Komis, I.
Makris, K. G.
Economou, E. N.
contents The problem of a single Hermitian impurity has long served as a cornerstone in condensed matter physics, offering fundamental insights into the mechanisms of Anderson localization. Yet, despite the increased interest in the spectral and localization properties of non-Hermitian lattices with defects, the non-Hermitian extension of the single impurity problem remains largely unexplored. In this work, we investigate the role of a single complex impurity in one-, two-, and three-dimensional infinite tight-binding lattices. Our study reveals a series of counterintuitive phenomena, including regions where localization vanishes and re-emerges as the impurity strength varies. Next, we study the corresponding finite-sized lattices, which are highly relevant to experimental realizations in readily accessible photonic platforms, revealing a variety of exotic features, such as scale-free localized states, exceptional points, and peculiar cross-shaped localized eigenstates, whose profiles deviate from the conventional exponential localization. This work paves the way for future studies on transport phenomena in non-Hermitian disordered lattices.
format Preprint
id arxiv_https___arxiv_org_abs_2511_17390
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-Hermitian impurity problem
Kokkinakis, E. T.
Komis, I.
Makris, K. G.
Economou, E. N.
Disordered Systems and Neural Networks
Optics
The problem of a single Hermitian impurity has long served as a cornerstone in condensed matter physics, offering fundamental insights into the mechanisms of Anderson localization. Yet, despite the increased interest in the spectral and localization properties of non-Hermitian lattices with defects, the non-Hermitian extension of the single impurity problem remains largely unexplored. In this work, we investigate the role of a single complex impurity in one-, two-, and three-dimensional infinite tight-binding lattices. Our study reveals a series of counterintuitive phenomena, including regions where localization vanishes and re-emerges as the impurity strength varies. Next, we study the corresponding finite-sized lattices, which are highly relevant to experimental realizations in readily accessible photonic platforms, revealing a variety of exotic features, such as scale-free localized states, exceptional points, and peculiar cross-shaped localized eigenstates, whose profiles deviate from the conventional exponential localization. This work paves the way for future studies on transport phenomena in non-Hermitian disordered lattices.
title Non-Hermitian impurity problem
topic Disordered Systems and Neural Networks
Optics
url https://arxiv.org/abs/2511.17390