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Main Authors: Yao, Zhiyuan, Zhang, Pengfei
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2410.21812
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author Yao, Zhiyuan
Zhang, Pengfei
author_facet Yao, Zhiyuan
Zhang, Pengfei
contents Quantum many-body scars (QMBS) -- rare eigenstates that evade thermalization -- are typically characterized by their low entanglement entropies compared to surrounding thermal eigenstates. However, due to finite-size effects in systems accessible via exact diagonalization, this measure can be ambiguous. To address this limitation, we propose using the correlation matrix spectrum as an alternative probe to identify QMBS. In cases of exact QMBS that either have known analytic expressions or are captured by various frameworks of QMBS, we find that the dimensionality of the null space of the correlation matrix -- an integer value, and thus immune to finite-size effects -- can qualitatively identify QMBS. Beyond serving as a diagnostic tool, the correlation matrix method enables the manipulation of the QMBS subspace. For approximate QMBS, such as those in the PXP model, we observe that the correlation matrix spectrum features numerous approximate zero eigenvalues, thereby distinguishing these states. We demonstrate the effectiveness and utility of this method with several paradigmatic QMBS examples.
format Preprint
id arxiv_https___arxiv_org_abs_2410_21812
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum many-body scars through the lens of correlation matrix
Yao, Zhiyuan
Zhang, Pengfei
Quantum Gases
Statistical Mechanics
Mathematical Physics
Quantum many-body scars (QMBS) -- rare eigenstates that evade thermalization -- are typically characterized by their low entanglement entropies compared to surrounding thermal eigenstates. However, due to finite-size effects in systems accessible via exact diagonalization, this measure can be ambiguous. To address this limitation, we propose using the correlation matrix spectrum as an alternative probe to identify QMBS. In cases of exact QMBS that either have known analytic expressions or are captured by various frameworks of QMBS, we find that the dimensionality of the null space of the correlation matrix -- an integer value, and thus immune to finite-size effects -- can qualitatively identify QMBS. Beyond serving as a diagnostic tool, the correlation matrix method enables the manipulation of the QMBS subspace. For approximate QMBS, such as those in the PXP model, we observe that the correlation matrix spectrum features numerous approximate zero eigenvalues, thereby distinguishing these states. We demonstrate the effectiveness and utility of this method with several paradigmatic QMBS examples.
title Quantum many-body scars through the lens of correlation matrix
topic Quantum Gases
Statistical Mechanics
Mathematical Physics
url https://arxiv.org/abs/2410.21812