Generalized conditional entropy optimization for qudit-qubit states

Autores
Gigena, Nicolás Alejandro; Rossignoli, Raúl Dante
Año de publicación
2014
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We derive a general approximate solution to the problem of minimizing the conditional entropy of a qudit-qubit system resulting from a local measurement on the qubit, which is valid for general entropic forms and becomes exact in the limit of weak correlations. This entropy measures the average conditional mixedness of the postmeasurement state of the qudit, and its minimum among all local measurements represents a generalized entanglement of formation. In the case of the von Neumann entropy, it is directly related to the quantum discord. It is shown that at the lowest nontrivial order, the problem reduces to the minimization of a quadratic form determined by the correlation tensor of the system, the Bloch vector of the qubit and the local concavity of the entropy, requiring just the diagonalization of a 3×3 matrix. A simple geometrical picture in terms of an associated correlation ellipsoid is also derived, which illustrates the link between entropy optimization and correlation access and which is exact for a quadratic entropy. The approach enables a simple estimation of the quantum discord. Illustrative results for two-qubit states are discussed.
Instituto de Física La Plata
Materia
Física
Conditional entropy
Von neumann entropy
Physics
Statistical physics
Quantum discord
Conditional quantum entropy
Quantum relative entropy
Joint quantum entropy
Binary entropy function
Generalized relative entropy
Quantum mechanics
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/126474

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network_name_str SEDICI (UNLP)
spelling Generalized conditional entropy optimization for qudit-qubit statesGigena, Nicolás AlejandroRossignoli, Raúl DanteFísicaConditional entropyVon neumann entropyPhysicsStatistical physicsQuantum discordConditional quantum entropyQuantum relative entropyJoint quantum entropyBinary entropy functionGeneralized relative entropyQuantum mechanicsWe derive a general approximate solution to the problem of minimizing the conditional entropy of a qudit-qubit system resulting from a local measurement on the qubit, which is valid for general entropic forms and becomes exact in the limit of weak correlations. This entropy measures the average conditional mixedness of the postmeasurement state of the qudit, and its minimum among all local measurements represents a generalized entanglement of formation. In the case of the von Neumann entropy, it is directly related to the quantum discord. It is shown that at the lowest nontrivial order, the problem reduces to the minimization of a quadratic form determined by the correlation tensor of the system, the Bloch vector of the qubit and the local concavity of the entropy, requiring just the diagonalization of a 3×3 matrix. A simple geometrical picture in terms of an associated correlation ellipsoid is also derived, which illustrates the link between entropy optimization and correlation access and which is exact for a quadratic entropy. The approach enables a simple estimation of the quantum discord. Illustrative results for two-qubit states are discussed.Instituto de Física La Plata2014-10-16info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/126474enginfo:eu-repo/semantics/altIdentifier/issn/1050-2947info:eu-repo/semantics/altIdentifier/issn/1094-1622info:eu-repo/semantics/altIdentifier/arxiv/1409.0807info:eu-repo/semantics/altIdentifier/doi/10.1103/physreva.90.042318info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-03T11:02:24Zoai:sedici.unlp.edu.ar:10915/126474Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-03 11:02:24.763SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Generalized conditional entropy optimization for qudit-qubit states
title Generalized conditional entropy optimization for qudit-qubit states
spellingShingle Generalized conditional entropy optimization for qudit-qubit states
Gigena, Nicolás Alejandro
Física
Conditional entropy
Von neumann entropy
Physics
Statistical physics
Quantum discord
Conditional quantum entropy
Quantum relative entropy
Joint quantum entropy
Binary entropy function
Generalized relative entropy
Quantum mechanics
title_short Generalized conditional entropy optimization for qudit-qubit states
title_full Generalized conditional entropy optimization for qudit-qubit states
title_fullStr Generalized conditional entropy optimization for qudit-qubit states
title_full_unstemmed Generalized conditional entropy optimization for qudit-qubit states
title_sort Generalized conditional entropy optimization for qudit-qubit states
dc.creator.none.fl_str_mv Gigena, Nicolás Alejandro
Rossignoli, Raúl Dante
author Gigena, Nicolás Alejandro
author_facet Gigena, Nicolás Alejandro
Rossignoli, Raúl Dante
author_role author
author2 Rossignoli, Raúl Dante
author2_role author
dc.subject.none.fl_str_mv Física
Conditional entropy
Von neumann entropy
Physics
Statistical physics
Quantum discord
Conditional quantum entropy
Quantum relative entropy
Joint quantum entropy
Binary entropy function
Generalized relative entropy
Quantum mechanics
topic Física
Conditional entropy
Von neumann entropy
Physics
Statistical physics
Quantum discord
Conditional quantum entropy
Quantum relative entropy
Joint quantum entropy
Binary entropy function
Generalized relative entropy
Quantum mechanics
dc.description.none.fl_txt_mv We derive a general approximate solution to the problem of minimizing the conditional entropy of a qudit-qubit system resulting from a local measurement on the qubit, which is valid for general entropic forms and becomes exact in the limit of weak correlations. This entropy measures the average conditional mixedness of the postmeasurement state of the qudit, and its minimum among all local measurements represents a generalized entanglement of formation. In the case of the von Neumann entropy, it is directly related to the quantum discord. It is shown that at the lowest nontrivial order, the problem reduces to the minimization of a quadratic form determined by the correlation tensor of the system, the Bloch vector of the qubit and the local concavity of the entropy, requiring just the diagonalization of a 3×3 matrix. A simple geometrical picture in terms of an associated correlation ellipsoid is also derived, which illustrates the link between entropy optimization and correlation access and which is exact for a quadratic entropy. The approach enables a simple estimation of the quantum discord. Illustrative results for two-qubit states are discussed.
Instituto de Física La Plata
description We derive a general approximate solution to the problem of minimizing the conditional entropy of a qudit-qubit system resulting from a local measurement on the qubit, which is valid for general entropic forms and becomes exact in the limit of weak correlations. This entropy measures the average conditional mixedness of the postmeasurement state of the qudit, and its minimum among all local measurements represents a generalized entanglement of formation. In the case of the von Neumann entropy, it is directly related to the quantum discord. It is shown that at the lowest nontrivial order, the problem reduces to the minimization of a quadratic form determined by the correlation tensor of the system, the Bloch vector of the qubit and the local concavity of the entropy, requiring just the diagonalization of a 3×3 matrix. A simple geometrical picture in terms of an associated correlation ellipsoid is also derived, which illustrates the link between entropy optimization and correlation access and which is exact for a quadratic entropy. The approach enables a simple estimation of the quantum discord. Illustrative results for two-qubit states are discussed.
publishDate 2014
dc.date.none.fl_str_mv 2014-10-16
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/126474
url http://sedici.unlp.edu.ar/handle/10915/126474
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/1050-2947
info:eu-repo/semantics/altIdentifier/issn/1094-1622
info:eu-repo/semantics/altIdentifier/arxiv/1409.0807
info:eu-repo/semantics/altIdentifier/doi/10.1103/physreva.90.042318
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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