Random Matrix Theory Approach to Quantum Fisher Information in Quantum Many-Body Systems

Fuente: arXiv
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Autori principali: Pavlov, Venelin P., Chorbadzhiyska, Yoana R., Nation, Charlie, Porras, Diego, Ivanov, Peter A.
Natura: Preprint
Pubblicazione: 2024
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author Pavlov, Venelin P.
Chorbadzhiyska, Yoana R.
Nation, Charlie
Porras, Diego
Ivanov, Peter A.
author_facet Pavlov, Venelin P.
Chorbadzhiyska, Yoana R.
Nation, Charlie
Porras, Diego
Ivanov, Peter A.
contents We theoretically investigate parameter quantum estimation in quantum chaotic systems. Our analysis is based on an effective description of non-integrable quantum systems in terms of a random matrix Hamiltonian. Based on this approach we derive an analytical expression for the time evolution of the quantum Fisher information. We test our random matrix theory prediction with the exact diagonalization of a non-integrable spin system, focusing on the estimation of a local magnetic field by measurements of the many-body state. Our numerical calculations agree with the effective random matrix theory approach and show that the information on the local Hamiltonian parameter is distributed throughout the quantum system during the quantum thermalization process. Our analysis shows a first stage in which the initial information spread is quadratic in time which quickly passes into linear increase with slope determine by the decay rate of the measured spin observable. When the information is fully spread among all degrees of freedom a second quadratic time scale determines the long time behaviour of the quantum Fisher information.
format Preprint
id arxiv_https___arxiv_org_abs_2402_09029
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Random Matrix Theory Approach to Quantum Fisher Information in Quantum Many-Body Systems
Pavlov, Venelin P.
Chorbadzhiyska, Yoana R.
Nation, Charlie
Porras, Diego
Ivanov, Peter A.
Quantum Physics
We theoretically investigate parameter quantum estimation in quantum chaotic systems. Our analysis is based on an effective description of non-integrable quantum systems in terms of a random matrix Hamiltonian. Based on this approach we derive an analytical expression for the time evolution of the quantum Fisher information. We test our random matrix theory prediction with the exact diagonalization of a non-integrable spin system, focusing on the estimation of a local magnetic field by measurements of the many-body state. Our numerical calculations agree with the effective random matrix theory approach and show that the information on the local Hamiltonian parameter is distributed throughout the quantum system during the quantum thermalization process. Our analysis shows a first stage in which the initial information spread is quadratic in time which quickly passes into linear increase with slope determine by the decay rate of the measured spin observable. When the information is fully spread among all degrees of freedom a second quadratic time scale determines the long time behaviour of the quantum Fisher information.
title Random Matrix Theory Approach to Quantum Fisher Information in Quantum Many-Body Systems
topic Quantum Physics
url https://arxiv.org/abs/2402.09029