Controlling Excitation Localization in Waveguide QED Systems

Fuente: arXiv
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Main Authors: Lee, C. -Y., Lin, K. -T., Lin, G. -D., Jen, H. H.
Format: Preprint
Published: 2025
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author Lee, C. -Y.
Lin, K. -T.
Lin, G. -D.
Jen, H. H.
author_facet Lee, C. -Y.
Lin, K. -T.
Lin, G. -D.
Jen, H. H.
contents We theoretically investigate excitation dynamics in one-dimensional arrays of quantum emitters coupled to a waveguide, focusing on localization and long-time population trapping. By combining time-domain simulations with spectral analysis of an effective non-Hermitian Hamiltonian, we identify two distinct mechanisms that give rise to localization: geometry-induced subradiance and disorder-induced Anderson-like confinement. Spatially modulated emitter arrangements--such as single- and double-Gaussian transverse profiles--enable long-lived subradiant modes even in the absence of disorder, with decay rates that can be finely controlled via geometric parameters. In contrast, localization in uniform arrays emerges only when disorder breaks spatial symmetry and suppresses collective emission through interference. We track the crossover between geometric and disorder-induced regimes, finding that double-Gaussian profiles exhibit clear spatial signatures of this transition, while single-Gaussian configurations display more gradual changes. These results establish geometry and disorder as complementary tools for engineering long-lived quantum states in waveguide QED systems, with direct relevance for scalable implementations in photonic platforms.
format Preprint
id arxiv_https___arxiv_org_abs_2505_20878
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Controlling Excitation Localization in Waveguide QED Systems
Lee, C. -Y.
Lin, K. -T.
Lin, G. -D.
Jen, H. H.
Quantum Physics
Atomic Physics
We theoretically investigate excitation dynamics in one-dimensional arrays of quantum emitters coupled to a waveguide, focusing on localization and long-time population trapping. By combining time-domain simulations with spectral analysis of an effective non-Hermitian Hamiltonian, we identify two distinct mechanisms that give rise to localization: geometry-induced subradiance and disorder-induced Anderson-like confinement. Spatially modulated emitter arrangements--such as single- and double-Gaussian transverse profiles--enable long-lived subradiant modes even in the absence of disorder, with decay rates that can be finely controlled via geometric parameters. In contrast, localization in uniform arrays emerges only when disorder breaks spatial symmetry and suppresses collective emission through interference. We track the crossover between geometric and disorder-induced regimes, finding that double-Gaussian profiles exhibit clear spatial signatures of this transition, while single-Gaussian configurations display more gradual changes. These results establish geometry and disorder as complementary tools for engineering long-lived quantum states in waveguide QED systems, with direct relevance for scalable implementations in photonic platforms.
title Controlling Excitation Localization in Waveguide QED Systems
topic Quantum Physics
Atomic Physics
url https://arxiv.org/abs/2505.20878