Optimizing nontrivial quantum observables using coherence

In this paper we consider the quantum resources required to maximize the mean values of any nontrivial quantum observable. We show that the task of maximizing the mean value of an observable is equivalent to maximizing some form of coherence, up to the application of an incoherent operation. For any...

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Main Authors: Kok Chuan Tan, Seongjeon Choi, Hyunseok Jeong
Format: Article
Language:English
Published: IOP Publishing 2019-01-01
Series:New Journal of Physics
Subjects:
Online Access:https://doi.org/10.1088/1367-2630/ab0430
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author Kok Chuan Tan
Seongjeon Choi
Hyunseok Jeong
author_facet Kok Chuan Tan
Seongjeon Choi
Hyunseok Jeong
author_sort Kok Chuan Tan
collection DOAJ
description In this paper we consider the quantum resources required to maximize the mean values of any nontrivial quantum observable. We show that the task of maximizing the mean value of an observable is equivalent to maximizing some form of coherence, up to the application of an incoherent operation. For any nontrivial observable, there always exists a set of preferred basis states where the superposition between such states is always useful for optimizing the mean value of a quantum observable. The usefulness of such states is expressed in terms of an infinitely large family of valid coherence measures which is then shown to be efficiently computable via a semidefinite program. We also show that these coherence measures respect a hierarchy that gives the robustness of coherence and the l _1 norm of coherence additional operational significance in terms of such optimization tasks.
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spelling doaj.art-e4e8a8a11bcb4980946810bb90f8290f2023-08-08T15:33:45ZengIOP PublishingNew Journal of Physics1367-26302019-01-0121202301310.1088/1367-2630/ab0430Optimizing nontrivial quantum observables using coherenceKok Chuan Tan0https://orcid.org/0000-0002-4025-1520Seongjeon Choi1Hyunseok Jeong2Center for Macroscopic Quantum Control & Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University , Seoul, 08826, Republic of KoreaCenter for Macroscopic Quantum Control & Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University , Seoul, 08826, Republic of KoreaCenter for Macroscopic Quantum Control & Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University , Seoul, 08826, Republic of KoreaIn this paper we consider the quantum resources required to maximize the mean values of any nontrivial quantum observable. We show that the task of maximizing the mean value of an observable is equivalent to maximizing some form of coherence, up to the application of an incoherent operation. For any nontrivial observable, there always exists a set of preferred basis states where the superposition between such states is always useful for optimizing the mean value of a quantum observable. The usefulness of such states is expressed in terms of an infinitely large family of valid coherence measures which is then shown to be efficiently computable via a semidefinite program. We also show that these coherence measures respect a hierarchy that gives the robustness of coherence and the l _1 norm of coherence additional operational significance in terms of such optimization tasks.https://doi.org/10.1088/1367-2630/ab0430quantum coherencequantum resource theoriesquantum information
spellingShingle Kok Chuan Tan
Seongjeon Choi
Hyunseok Jeong
Optimizing nontrivial quantum observables using coherence
New Journal of Physics
quantum coherence
quantum resource theories
quantum information
title Optimizing nontrivial quantum observables using coherence
title_full Optimizing nontrivial quantum observables using coherence
title_fullStr Optimizing nontrivial quantum observables using coherence
title_full_unstemmed Optimizing nontrivial quantum observables using coherence
title_short Optimizing nontrivial quantum observables using coherence
title_sort optimizing nontrivial quantum observables using coherence
topic quantum coherence
quantum resource theories
quantum information
url https://doi.org/10.1088/1367-2630/ab0430
work_keys_str_mv AT kokchuantan optimizingnontrivialquantumobservablesusingcoherence
AT seongjeonchoi optimizingnontrivialquantumobservablesusingcoherence
AT hyunseokjeong optimizingnontrivialquantumobservablesusingcoherence