General theory of measurement with two copies of a quantum state

We analyze the results of the most general measurement on two copies of a quantum state. We show that by using two copies of a quantum state it is possible to achieve an exponential improvement with respect to known methods for quantum state tomography. We demonstrate that μ can label a set of outco...

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Autores principales: Bendersky, A., Paz, J.P., Cunha, M.T.
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00319007_v103_n4_p_Bendersky
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spelling todo:paper_00319007_v103_n4_p_Bendersky2023-10-03T14:42:05Z General theory of measurement with two copies of a quantum state Bendersky, A. Paz, J.P. Cunha, M.T. Completely positive Copositive General theory Positive operator valued measure Quantum state Quantum state tomography Labels Tomography Quantum theory We analyze the results of the most general measurement on two copies of a quantum state. We show that by using two copies of a quantum state it is possible to achieve an exponential improvement with respect to known methods for quantum state tomography. We demonstrate that μ can label a set of outcomes of a measurement on two copies if and only if there is a family of maps Cμ such that the probability Prob(μ) is the fidelity of each map, i.e., Prob(μ)=Tr[ρCμ(ρ)]. Here, the map Cμ must be completely positive after being composed with the transposition (these are called completely copositive, or CCP, maps) and must add up to the fully depolarizing map. This implies that a positive operator valued measure on two copies induces a measure on the set of CCP maps (i.e., a CCP map valued measure). © 2009 The American Physical Society. Fil:Bendersky, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Paz, J.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00319007_v103_n4_p_Bendersky
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Completely positive
Copositive
General theory
Positive operator valued measure
Quantum state
Quantum state tomography
Labels
Tomography
Quantum theory
spellingShingle Completely positive
Copositive
General theory
Positive operator valued measure
Quantum state
Quantum state tomography
Labels
Tomography
Quantum theory
Bendersky, A.
Paz, J.P.
Cunha, M.T.
General theory of measurement with two copies of a quantum state
topic_facet Completely positive
Copositive
General theory
Positive operator valued measure
Quantum state
Quantum state tomography
Labels
Tomography
Quantum theory
description We analyze the results of the most general measurement on two copies of a quantum state. We show that by using two copies of a quantum state it is possible to achieve an exponential improvement with respect to known methods for quantum state tomography. We demonstrate that μ can label a set of outcomes of a measurement on two copies if and only if there is a family of maps Cμ such that the probability Prob(μ) is the fidelity of each map, i.e., Prob(μ)=Tr[ρCμ(ρ)]. Here, the map Cμ must be completely positive after being composed with the transposition (these are called completely copositive, or CCP, maps) and must add up to the fully depolarizing map. This implies that a positive operator valued measure on two copies induces a measure on the set of CCP maps (i.e., a CCP map valued measure). © 2009 The American Physical Society.
format JOUR
author Bendersky, A.
Paz, J.P.
Cunha, M.T.
author_facet Bendersky, A.
Paz, J.P.
Cunha, M.T.
author_sort Bendersky, A.
title General theory of measurement with two copies of a quantum state
title_short General theory of measurement with two copies of a quantum state
title_full General theory of measurement with two copies of a quantum state
title_fullStr General theory of measurement with two copies of a quantum state
title_full_unstemmed General theory of measurement with two copies of a quantum state
title_sort general theory of measurement with two copies of a quantum state
url http://hdl.handle.net/20.500.12110/paper_00319007_v103_n4_p_Bendersky
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