Krylov complexity in quantum many-body scars of spin-1 models

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Hauptverfasser: Hu, Qingmin, Zhang, Wen-Yi, Han, Yunguang, You, Wen-Long
Format: Preprint
Veröffentlicht: 2025
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author Hu, Qingmin
Zhang, Wen-Yi
Han, Yunguang
You, Wen-Long
author_facet Hu, Qingmin
Zhang, Wen-Yi
Han, Yunguang
You, Wen-Long
contents Weak ergodicity breaking, particularly through quantum many-body scars (QMBS), has become a significant focus in many-body physics. Krylov state complexity quantifies the spread of quantum states within the Krylov basis and serves as a powerful diagnostic for analyzing nonergodic dynamics. In this work, we study spin-one XXZ magnets and reveal nonergodic behavior tied to QMBS. For the XY model, the nematic Néel state exhibits periodic revivals in Krylov complexity. In the generic XXZ model, we identify spin helix states as weakly ergodicity-breaking states, characterized by low entanglement and nonthermal dynamics. Across different scenarios, the Lanczos coefficients for scarred states display an elliptical pattern, reflecting a hidden SU(2) algebra that enables analytical results for Krylov complexity and fidelity. These findings, which exemplify the rare capability to characterize QMBS analytically, are feasible with current experimental techniques and offer deep insights into the nonergodic dynamics of interacting quantum systems.
format Preprint
id arxiv_https___arxiv_org_abs_2503_24073
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Krylov complexity in quantum many-body scars of spin-1 models
Hu, Qingmin
Zhang, Wen-Yi
Han, Yunguang
You, Wen-Long
Strongly Correlated Electrons
Weak ergodicity breaking, particularly through quantum many-body scars (QMBS), has become a significant focus in many-body physics. Krylov state complexity quantifies the spread of quantum states within the Krylov basis and serves as a powerful diagnostic for analyzing nonergodic dynamics. In this work, we study spin-one XXZ magnets and reveal nonergodic behavior tied to QMBS. For the XY model, the nematic Néel state exhibits periodic revivals in Krylov complexity. In the generic XXZ model, we identify spin helix states as weakly ergodicity-breaking states, characterized by low entanglement and nonthermal dynamics. Across different scenarios, the Lanczos coefficients for scarred states display an elliptical pattern, reflecting a hidden SU(2) algebra that enables analytical results for Krylov complexity and fidelity. These findings, which exemplify the rare capability to characterize QMBS analytically, are feasible with current experimental techniques and offer deep insights into the nonergodic dynamics of interacting quantum systems.
title Krylov complexity in quantum many-body scars of spin-1 models
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2503.24073