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Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge
Quantum measurements have intrinsic properties that seem incompatible with our everyday-life macroscopic measurements. Macroscopic Quantum Measurement (MQM) is a concept that aims at bridging the gap between well-understood microscopic quantum measurements and macroscopic classical measurements. In...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7512233/ https://www.ncbi.nlm.nih.gov/pubmed/33265124 http://dx.doi.org/10.3390/e20010039 |
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author | Renou, Marc-Olivier Gisin, Nicolas Fröwis, Florian |
author_facet | Renou, Marc-Olivier Gisin, Nicolas Fröwis, Florian |
author_sort | Renou, Marc-Olivier |
collection | PubMed |
description | Quantum measurements have intrinsic properties that seem incompatible with our everyday-life macroscopic measurements. Macroscopic Quantum Measurement (MQM) is a concept that aims at bridging the gap between well-understood microscopic quantum measurements and macroscopic classical measurements. In this paper, we focus on the task of the polarization direction estimation of a system of N spins 1/2 particles and investigate the model some of us proposed in Barnea et al., 2017. This model is based on a von Neumann pointer measurement, where each spin component of the system is coupled to one of the three spatial component directions of a pointer. It shows traits of a classical measurement for an intermediate coupling strength. We investigate relaxations of the assumptions on the initial knowledge about the state and on the control over the MQM. We show that the model is robust with regard to these relaxations. It performs well for thermal states and a lack of knowledge about the size of the system. Furthermore, a lack of control on the MQM can be compensated by repeated “ultra-weak” measurements. |
format | Online Article Text |
id | pubmed-7512233 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-75122332020-11-09 Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge Renou, Marc-Olivier Gisin, Nicolas Fröwis, Florian Entropy (Basel) Article Quantum measurements have intrinsic properties that seem incompatible with our everyday-life macroscopic measurements. Macroscopic Quantum Measurement (MQM) is a concept that aims at bridging the gap between well-understood microscopic quantum measurements and macroscopic classical measurements. In this paper, we focus on the task of the polarization direction estimation of a system of N spins 1/2 particles and investigate the model some of us proposed in Barnea et al., 2017. This model is based on a von Neumann pointer measurement, where each spin component of the system is coupled to one of the three spatial component directions of a pointer. It shows traits of a classical measurement for an intermediate coupling strength. We investigate relaxations of the assumptions on the initial knowledge about the state and on the control over the MQM. We show that the model is robust with regard to these relaxations. It performs well for thermal states and a lack of knowledge about the size of the system. Furthermore, a lack of control on the MQM can be compensated by repeated “ultra-weak” measurements. MDPI 2018-01-09 /pmc/articles/PMC7512233/ /pubmed/33265124 http://dx.doi.org/10.3390/e20010039 Text en © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Renou, Marc-Olivier Gisin, Nicolas Fröwis, Florian Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge |
title | Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge |
title_full | Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge |
title_fullStr | Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge |
title_full_unstemmed | Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge |
title_short | Robust Macroscopic Quantum Measurements in the Presence of Limited Control and Knowledge |
title_sort | robust macroscopic quantum measurements in the presence of limited control and knowledge |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7512233/ https://www.ncbi.nlm.nih.gov/pubmed/33265124 http://dx.doi.org/10.3390/e20010039 |
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