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Quantum metrology with unitary parametrization processes

Quantum Fisher information is a central quantity in quantum metrology. We discuss an alternative representation of quantum Fisher information for unitary parametrization processes. In this representation, all information of parametrization transformation, i.e., the entire dynamical information, is t...

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Detalles Bibliográficos
Autores principales: Liu, Jing, Jing, Xiao-Xing, Wang, Xiaoguang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338430/
https://www.ncbi.nlm.nih.gov/pubmed/25708678
http://dx.doi.org/10.1038/srep08565
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author Liu, Jing
Jing, Xiao-Xing
Wang, Xiaoguang
author_facet Liu, Jing
Jing, Xiao-Xing
Wang, Xiaoguang
author_sort Liu, Jing
collection PubMed
description Quantum Fisher information is a central quantity in quantum metrology. We discuss an alternative representation of quantum Fisher information for unitary parametrization processes. In this representation, all information of parametrization transformation, i.e., the entire dynamical information, is totally involved in a Hermitian operator [Image: see text]. Utilizing this representation, quantum Fisher information is only determined by [Image: see text] and the initial state. Furthermore, [Image: see text] can be expressed in an expanded form. The highlights of this form is that it can bring great convenience during the calculation for the Hamiltonians owning recursive commutations with their partial derivative. We apply this representation in a collective spin system and show the specific expression of [Image: see text]. For a simple case, a spin-half system, the quantum Fisher information is given and the optimal states to access maximum quantum Fisher information are found. Moreover, for an exponential form initial state, an analytical expression of quantum Fisher information by [Image: see text] operator is provided. The multiparameter quantum metrology is also considered and discussed utilizing this representation.
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spelling pubmed-43384302015-03-04 Quantum metrology with unitary parametrization processes Liu, Jing Jing, Xiao-Xing Wang, Xiaoguang Sci Rep Article Quantum Fisher information is a central quantity in quantum metrology. We discuss an alternative representation of quantum Fisher information for unitary parametrization processes. In this representation, all information of parametrization transformation, i.e., the entire dynamical information, is totally involved in a Hermitian operator [Image: see text]. Utilizing this representation, quantum Fisher information is only determined by [Image: see text] and the initial state. Furthermore, [Image: see text] can be expressed in an expanded form. The highlights of this form is that it can bring great convenience during the calculation for the Hamiltonians owning recursive commutations with their partial derivative. We apply this representation in a collective spin system and show the specific expression of [Image: see text]. For a simple case, a spin-half system, the quantum Fisher information is given and the optimal states to access maximum quantum Fisher information are found. Moreover, for an exponential form initial state, an analytical expression of quantum Fisher information by [Image: see text] operator is provided. The multiparameter quantum metrology is also considered and discussed utilizing this representation. Nature Publishing Group 2015-02-24 /pmc/articles/PMC4338430/ /pubmed/25708678 http://dx.doi.org/10.1038/srep08565 Text en Copyright © 2015, Macmillan Publishers Limited. All rights reserved http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder in order to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Liu, Jing
Jing, Xiao-Xing
Wang, Xiaoguang
Quantum metrology with unitary parametrization processes
title Quantum metrology with unitary parametrization processes
title_full Quantum metrology with unitary parametrization processes
title_fullStr Quantum metrology with unitary parametrization processes
title_full_unstemmed Quantum metrology with unitary parametrization processes
title_short Quantum metrology with unitary parametrization processes
title_sort quantum metrology with unitary parametrization processes
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338430/
https://www.ncbi.nlm.nih.gov/pubmed/25708678
http://dx.doi.org/10.1038/srep08565
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