Information scrambling in quantum walks: Discrete-time formulation of Krylov complexity

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Auteur principal: Sahu, Himanshu
Format: Preprint
Publié: 2024
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author Sahu, Himanshu
author_facet Sahu, Himanshu
contents We study information scrambling -- a spread of initially localized quantum information into the system's many degree of freedom -- in discrete-time quantum walks. We consider out-of-time-ordered correlators (OTOC) and K-complexity as a probe of information scrambling. The OTOC for local spin operators in all directions has a light-cone structure which is ``shell-like''. As the wavefront passes, the OTOC approaches to zero in the long-time limit, showing no signature of scrambling. The introduction of spatial or temporal disorder changes the shape of the light-cone akin to localization of wavefunction. We formulate the K-complexity in system with discrete-time evolution, and show that it grows linearly in discrete-time quantum walk. The presence of disorder modifies this growth to sub-linear. Our study present interesting case to explore many-body phenomenon in a discrete-time quantum walk using scrambling.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05865
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Information scrambling in quantum walks: Discrete-time formulation of Krylov complexity
Sahu, Himanshu
Quantum Physics
Disordered Systems and Neural Networks
We study information scrambling -- a spread of initially localized quantum information into the system's many degree of freedom -- in discrete-time quantum walks. We consider out-of-time-ordered correlators (OTOC) and K-complexity as a probe of information scrambling. The OTOC for local spin operators in all directions has a light-cone structure which is ``shell-like''. As the wavefront passes, the OTOC approaches to zero in the long-time limit, showing no signature of scrambling. The introduction of spatial or temporal disorder changes the shape of the light-cone akin to localization of wavefunction. We formulate the K-complexity in system with discrete-time evolution, and show that it grows linearly in discrete-time quantum walk. The presence of disorder modifies this growth to sub-linear. Our study present interesting case to explore many-body phenomenon in a discrete-time quantum walk using scrambling.
title Information scrambling in quantum walks: Discrete-time formulation of Krylov complexity
topic Quantum Physics
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2406.05865