Operator growth and spread complexity in open quantum systems

Fuente: arXiv
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Hauptverfasser: Carolan, Eoin, Kiely, Anthony, Campbell, Steve, Deffner, Sebastian
Format: Preprint
Veröffentlicht: 2024
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author Carolan, Eoin
Kiely, Anthony
Campbell, Steve
Deffner, Sebastian
author_facet Carolan, Eoin
Kiely, Anthony
Campbell, Steve
Deffner, Sebastian
contents Commonly, the notion of "quantum chaos'' refers to the fast scrambling of information throughout complex quantum systems undergoing unitary evolution. Motivated by the Krylov complexity and the operator growth hypothesis, we demonstrate that the entropy of the population distribution for an operator in time is a useful way to capture the complexity of the internal information dynamics of a system when subject to an environment and is, in principle, agnostic to the specific choice of operator basis. We demonstrate its effectiveness for the Sachdev-Ye-Kitaev (SYK) model, examining the dynamics of the system in both its Krylov basis and the basis of operator strings. We prove that the former basis minimises spread complexity while the latter is an eigenbasis for high dissipation. In both cases, we probe the long-time dynamics of the model and the phenomenological effects of decoherence on the complexity of the dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2404_03529
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Operator growth and spread complexity in open quantum systems
Carolan, Eoin
Kiely, Anthony
Campbell, Steve
Deffner, Sebastian
Quantum Physics
Statistical Mechanics
Commonly, the notion of "quantum chaos'' refers to the fast scrambling of information throughout complex quantum systems undergoing unitary evolution. Motivated by the Krylov complexity and the operator growth hypothesis, we demonstrate that the entropy of the population distribution for an operator in time is a useful way to capture the complexity of the internal information dynamics of a system when subject to an environment and is, in principle, agnostic to the specific choice of operator basis. We demonstrate its effectiveness for the Sachdev-Ye-Kitaev (SYK) model, examining the dynamics of the system in both its Krylov basis and the basis of operator strings. We prove that the former basis minimises spread complexity while the latter is an eigenbasis for high dissipation. In both cases, we probe the long-time dynamics of the model and the phenomenological effects of decoherence on the complexity of the dynamics.
title Operator growth and spread complexity in open quantum systems
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2404.03529