Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection

We study a model of a two-level system (i.e. a qubit) in interaction with the electromagnetic field. By means of homodyne detection, one field-quadrature is observed continuously in time. Due to the interaction, information about the initial state of the qubit is transferred into the field, thus inf...

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Bibliographic Details
Main Authors: Janssens, B, Bouten, L
Language:English
Published: 2005
Subjects:
General Theoretical Physics
The Pointers
Online Access:http://cds.cern.ch/record/895969
id ftcern:oai:cds.cern.ch:895969
record_format openpolar
spelling ftcern:oai:cds.cern.ch:895969 2023-05-15T18:32:38+02:00 Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection Janssens, B Bouten, L 2005-10-12 http://cds.cern.ch/record/895969 eng eng http://cds.cern.ch/record/895969 quant-ph/0510086 oai:cds.cern.ch:895969 General Theoretical Physics 2005 ftcern 2018-07-28T07:52:02Z We study a model of a two-level system (i.e. a qubit) in interaction with the electromagnetic field. By means of homodyne detection, one field-quadrature is observed continuously in time. Due to the interaction, information about the initial state of the qubit is transferred into the field, thus influencing the homodyne measurement results. We construct random variables (pointers) on the probability space of homodyne measurement outcomes having distributions close to the initial distributions of sigma-x and sigma-z. Using variational calculus, we find the pointers that are optimal. These optimal pointers are very close to hitting the bound imposed by Heisenberg's uncertainty relation on joint measurement of two non-commuting observables. We close the paper by giving the probability densities of the pointers. Other/Unknown Material The Pointers CERN Document Server (CDS)
institution Open Polar
collection CERN Document Server (CDS)
op_collection_id ftcern
language English
topic General Theoretical Physics
spellingShingle General Theoretical Physics
Janssens, B
Bouten, L
Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection
topic_facet General Theoretical Physics
description We study a model of a two-level system (i.e. a qubit) in interaction with the electromagnetic field. By means of homodyne detection, one field-quadrature is observed continuously in time. Due to the interaction, information about the initial state of the qubit is transferred into the field, thus influencing the homodyne measurement results. We construct random variables (pointers) on the probability space of homodyne measurement outcomes having distributions close to the initial distributions of sigma-x and sigma-z. Using variational calculus, we find the pointers that are optimal. These optimal pointers are very close to hitting the bound imposed by Heisenberg's uncertainty relation on joint measurement of two non-commuting observables. We close the paper by giving the probability densities of the pointers.
author Janssens, B
Bouten, L
author_facet Janssens, B
Bouten, L
author_sort Janssens, B
title Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection
title_short Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection
title_full Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection
title_fullStr Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection
title_full_unstemmed Optimal Pointers for Joint Measurement of sigma-x and sigma-z via Homodyne Detection
title_sort optimal pointers for joint measurement of sigma-x and sigma-z via homodyne detection
publishDate 2005
url http://cds.cern.ch/record/895969
genre The Pointers
genre_facet The Pointers
op_relation http://cds.cern.ch/record/895969
quant-ph/0510086
oai:cds.cern.ch:895969
_version_ 1766216840617394176

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