Probing the localization effects in Krylov basis

Fuente: arXiv
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Main Authors: Kannan, J. Bharathi, PG, Sreeram, Paul, Sanku, Tekur, S. Harshini, Santhanam, M. S.
Format: Preprint
Published: 2025
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author Kannan, J. Bharathi
PG, Sreeram
Paul, Sanku
Tekur, S. Harshini
Santhanam, M. S.
author_facet Kannan, J. Bharathi
PG, Sreeram
Paul, Sanku
Tekur, S. Harshini
Santhanam, M. S.
contents Krylov complexity (K-complexity) is a measure of quantum state complexity that minimizes wavefunction spreading across all the possible bases. It serves as a key indicator of operator growth and quantum chaos. In this work, K-complexity and Arnoldi coefficients are applied to probe a variety of localization phenomena in the quantum kicked rotor system. We analyze four distinct localization scenarios -- ranging from compact localization effect arising from quantum anti-resonance to a weaker form of power-law localization -- each one exhibiting distinct K-complexity signatures and Arnoldi coefficient variations. In general, K-complexity not only indicates the degree of localization, but surprisingly also of the nature of localization. In particular, the long-time behaviour of K-complexity and the wavefunction evolution on Krylov chain can distinguish various types of observed localization in QKR. In particular, the time-averaged K-complexity and scaling of the variance of Arnoldi coefficients with effective Planck's constant can distinguish the localization effects induced by the classical regular phase structures and the dynamical localization arising from quantum interferences. Further, the Arnoldi coefficient is shown to capture the transition from integrability to chaos as well. This work shows how localization dynamics manifests in the Krylov basis.
format Preprint
id arxiv_https___arxiv_org_abs_2503_23334
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Probing the localization effects in Krylov basis
Kannan, J. Bharathi
PG, Sreeram
Paul, Sanku
Tekur, S. Harshini
Santhanam, M. S.
Quantum Physics
Krylov complexity (K-complexity) is a measure of quantum state complexity that minimizes wavefunction spreading across all the possible bases. It serves as a key indicator of operator growth and quantum chaos. In this work, K-complexity and Arnoldi coefficients are applied to probe a variety of localization phenomena in the quantum kicked rotor system. We analyze four distinct localization scenarios -- ranging from compact localization effect arising from quantum anti-resonance to a weaker form of power-law localization -- each one exhibiting distinct K-complexity signatures and Arnoldi coefficient variations. In general, K-complexity not only indicates the degree of localization, but surprisingly also of the nature of localization. In particular, the long-time behaviour of K-complexity and the wavefunction evolution on Krylov chain can distinguish various types of observed localization in QKR. In particular, the time-averaged K-complexity and scaling of the variance of Arnoldi coefficients with effective Planck's constant can distinguish the localization effects induced by the classical regular phase structures and the dynamical localization arising from quantum interferences. Further, the Arnoldi coefficient is shown to capture the transition from integrability to chaos as well. This work shows how localization dynamics manifests in the Krylov basis.
title Probing the localization effects in Krylov basis
topic Quantum Physics
url https://arxiv.org/abs/2503.23334