The power of a control qubit in weak measurements

Abstract In the late 80 s, a curious effect suggested by Aharanov et al. was found to lead to an anomalous amplification based on quantum measurements of weakly coupled systems. In this paper, we investigate the quantum control of the weak value amplification of a qubit system coupled to a meter. Fo...

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Autores principales:	Raul Coto, Víctor Montenegro, Vitalie Eremeev, Douglas Mundarain, Miguel Orszag
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/74214a8e0de34a07ab59693871d355e3
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spelling	oai:doaj.org-article:74214a8e0de34a07ab59693871d355e32021-12-02T12:31:52ZThe power of a control qubit in weak measurements10.1038/s41598-017-05370-52045-2322https://doaj.org/article/74214a8e0de34a07ab59693871d355e32017-07-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-05370-5https://doaj.org/toc/2045-2322Abstract In the late 80 s, a curious effect suggested by Aharanov et al. was found to lead to an anomalous amplification based on quantum measurements of weakly coupled systems. In this paper, we investigate the quantum control of the weak value amplification of a qubit system coupled to a meter. For the qubit system, the coupling occurs via a second non-interacting qubit, initially quantum correlated with the first one. We show that for weak measurements, the control can be remotely realized via the post-selected state of the second qubit or the degree of squeezing of the meter. In our study of the quantum control of the amplification, we can easily manipulate the degree of quantum correlations between the initially correlated qubits. We find that the degree of entanglement has no effect on the quantum control of the amplification. However, we also found a clear connection between the amplification and quantum discord like measurements as well as classical correlations between the qubits. Finally, we suggest an application of the amplification control on the enhancement of the quantum measurement accuracy, e.g. measuring the relative phase of the post-selected control qubit in a more precise way, as opposed to the non-amplified case.Raul CotoVíctor MontenegroVitalie EremeevDouglas MundarainMiguel OrszagNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-11 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Raul Coto Víctor Montenegro Vitalie Eremeev Douglas Mundarain Miguel Orszag The power of a control qubit in weak measurements
description	Abstract In the late 80 s, a curious effect suggested by Aharanov et al. was found to lead to an anomalous amplification based on quantum measurements of weakly coupled systems. In this paper, we investigate the quantum control of the weak value amplification of a qubit system coupled to a meter. For the qubit system, the coupling occurs via a second non-interacting qubit, initially quantum correlated with the first one. We show that for weak measurements, the control can be remotely realized via the post-selected state of the second qubit or the degree of squeezing of the meter. In our study of the quantum control of the amplification, we can easily manipulate the degree of quantum correlations between the initially correlated qubits. We find that the degree of entanglement has no effect on the quantum control of the amplification. However, we also found a clear connection between the amplification and quantum discord like measurements as well as classical correlations between the qubits. Finally, we suggest an application of the amplification control on the enhancement of the quantum measurement accuracy, e.g. measuring the relative phase of the post-selected control qubit in a more precise way, as opposed to the non-amplified case.
format	article
author	Raul Coto Víctor Montenegro Vitalie Eremeev Douglas Mundarain Miguel Orszag
author_facet	Raul Coto Víctor Montenegro Vitalie Eremeev Douglas Mundarain Miguel Orszag
author_sort	Raul Coto
title	The power of a control qubit in weak measurements
title_short	The power of a control qubit in weak measurements
title_full	The power of a control qubit in weak measurements
title_fullStr	The power of a control qubit in weak measurements
title_full_unstemmed	The power of a control qubit in weak measurements
title_sort	power of a control qubit in weak measurements
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/74214a8e0de34a07ab59693871d355e3
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The power of a control qubit in weak measurements

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