---
_id: '16101'
abstract:
- lang: eng
  text: <jats:title>Abstract</jats:title><jats:p>The nonorthogonality of coherent
    states is a fundamental property which prevents them from being perfectly and
    deterministically discriminated. Here, we present an experimentally feasible protocol
    for the probabilistic orthogonalisation of a pair of coherent states, independent
    of their amplitude and phase. In contrast to unambiguous state discrimination,
    a successful operation of our protocol is heralded without measuring the states.
    As such, they remain suitable for further manipulation and the obtained orthogonal
    states serve as a discretevariable basis. Therefore, our protocol doubles as a
    simple continuous-to-discrete variable converter, which may find application in
    hybrid continuous-discrete quantum information processing protocols.</jats:p>
author:
- first_name: Regina
  full_name: Kruse, Regina
  last_name: Kruse
- first_name: Christine
  full_name: Silberhorn, Christine
  id: '26263'
  last_name: Silberhorn
- first_name: Tim
  full_name: Bartley, Tim
  id: '49683'
  last_name: Bartley
citation:
  ama: Kruse R, Silberhorn C, Bartley T. Heralded orthogonalisation of coherent states
    and their conversion to discrete-variable superpositions. <i>Quantum Measurements
    and Quantum Metrology</i>. 2018;4(1). doi:<a href="https://doi.org/10.1515/qmetro-2017-0005">10.1515/qmetro-2017-0005</a>
  apa: Kruse, R., Silberhorn, C., &#38; Bartley, T. (2018). Heralded orthogonalisation
    of coherent states and their conversion to discrete-variable superpositions. <i>Quantum
    Measurements and Quantum Metrology</i>, <i>4</i>(1). <a href="https://doi.org/10.1515/qmetro-2017-0005">https://doi.org/10.1515/qmetro-2017-0005</a>
  bibtex: '@article{Kruse_Silberhorn_Bartley_2018, title={Heralded orthogonalisation
    of coherent states and their conversion to discrete-variable superpositions},
    volume={4}, DOI={<a href="https://doi.org/10.1515/qmetro-2017-0005">10.1515/qmetro-2017-0005</a>},
    number={1}, journal={Quantum Measurements and Quantum Metrology}, author={Kruse,
    Regina and Silberhorn, Christine and Bartley, Tim}, year={2018} }'
  chicago: Kruse, Regina, Christine Silberhorn, and Tim Bartley. “Heralded Orthogonalisation
    of Coherent States and Their Conversion to Discrete-Variable Superpositions.”
    <i>Quantum Measurements and Quantum Metrology</i> 4, no. 1 (2018). <a href="https://doi.org/10.1515/qmetro-2017-0005">https://doi.org/10.1515/qmetro-2017-0005</a>.
  ieee: R. Kruse, C. Silberhorn, and T. Bartley, “Heralded orthogonalisation of coherent
    states and their conversion to discrete-variable superpositions,” <i>Quantum Measurements
    and Quantum Metrology</i>, vol. 4, no. 1, 2018.
  mla: Kruse, Regina, et al. “Heralded Orthogonalisation of Coherent States and Their
    Conversion to Discrete-Variable Superpositions.” <i>Quantum Measurements and Quantum
    Metrology</i>, vol. 4, no. 1, 2018, doi:<a href="https://doi.org/10.1515/qmetro-2017-0005">10.1515/qmetro-2017-0005</a>.
  short: R. Kruse, C. Silberhorn, T. Bartley, Quantum Measurements and Quantum Metrology
    4 (2018).
date_created: 2020-02-26T14:51:18Z
date_updated: 2022-01-06T06:52:43Z
department:
- _id: '15'
doi: 10.1515/qmetro-2017-0005
intvolume: '         4'
issue: '1'
language:
- iso: eng
publication: Quantum Measurements and Quantum Metrology
publication_identifier:
  issn:
  - 2299-114X
publication_status: published
status: public
title: Heralded orthogonalisation of coherent states and their conversion to discrete-variable
  superpositions
type: journal_article
user_id: '49683'
volume: 4
year: '2018'
...
---
_id: '9836'
abstract:
- lang: eng
  text: <jats:title>Abstract</jats:title><jats:p>Quantum mechanics establishes the
    ultimate limit to the scaling of the precision on any parameter, by identifying
    optimal probe states and measurements. While this paradigm is, at least in principle,
    adequate for the metrology of quantum channels involving the estimation of phase
    and loss parameters, we show that estimating the loss parameters associated with
    a quantum channel and a realistic quantum detector are fundamentally different.
    While Fock states are provably optimal for the former, we identify a crossover
    in the nature of the optimal probe state for estimating detector imperfections
    as a function of the loss parameter using Fisher information as a benchmark. We
    provide theoretical results for on-off and homodyne detectors, the most widely
    used detectors in quantum photonics technologies, when using Fock states and coherent
    states as probes.</jats:p>
author:
- first_name: Marco
  full_name: Barbieri, Marco
  last_name: Barbieri
- first_name: Animesh
  full_name: Datta, Animesh
  last_name: Datta
- first_name: Tim
  full_name: Bartley, Tim
  id: '49683'
  last_name: Bartley
- first_name: Xian-Min
  full_name: Jin, Xian-Min
  last_name: Jin
- first_name: W. Steven
  full_name: Kolthammer, W. Steven
  last_name: Kolthammer
- first_name: Ian A.
  full_name: Walmsley, Ian A.
  last_name: Walmsley
citation:
  ama: Barbieri M, Datta A, Bartley T, Jin X-M, Kolthammer WS, Walmsley IA. Quantum
    enhanced estimation of optical detector efficiencies. <i>Quantum Measurements
    and Quantum Metrology</i>. 2016. doi:<a href="https://doi.org/10.1515/qmetro-2016-0002">10.1515/qmetro-2016-0002</a>
  apa: Barbieri, M., Datta, A., Bartley, T., Jin, X.-M., Kolthammer, W. S., &#38;
    Walmsley, I. A. (2016). Quantum enhanced estimation of optical detector efficiencies.
    <i>Quantum Measurements and Quantum Metrology</i>. <a href="https://doi.org/10.1515/qmetro-2016-0002">https://doi.org/10.1515/qmetro-2016-0002</a>
  bibtex: '@article{Barbieri_Datta_Bartley_Jin_Kolthammer_Walmsley_2016, title={Quantum
    enhanced estimation of optical detector efficiencies}, DOI={<a href="https://doi.org/10.1515/qmetro-2016-0002">10.1515/qmetro-2016-0002</a>},
    journal={Quantum Measurements and Quantum Metrology}, author={Barbieri, Marco
    and Datta, Animesh and Bartley, Tim and Jin, Xian-Min and Kolthammer, W. Steven
    and Walmsley, Ian A.}, year={2016} }'
  chicago: Barbieri, Marco, Animesh Datta, Tim Bartley, Xian-Min Jin, W. Steven Kolthammer,
    and Ian A. Walmsley. “Quantum Enhanced Estimation of Optical Detector Efficiencies.”
    <i>Quantum Measurements and Quantum Metrology</i>, 2016. <a href="https://doi.org/10.1515/qmetro-2016-0002">https://doi.org/10.1515/qmetro-2016-0002</a>.
  ieee: M. Barbieri, A. Datta, T. Bartley, X.-M. Jin, W. S. Kolthammer, and I. A.
    Walmsley, “Quantum enhanced estimation of optical detector efficiencies,” <i>Quantum
    Measurements and Quantum Metrology</i>, 2016.
  mla: Barbieri, Marco, et al. “Quantum Enhanced Estimation of Optical Detector Efficiencies.”
    <i>Quantum Measurements and Quantum Metrology</i>, 2016, doi:<a href="https://doi.org/10.1515/qmetro-2016-0002">10.1515/qmetro-2016-0002</a>.
  short: M. Barbieri, A. Datta, T. Bartley, X.-M. Jin, W.S. Kolthammer, I.A. Walmsley,
    Quantum Measurements and Quantum Metrology (2016).
date_created: 2019-05-17T14:08:35Z
date_updated: 2020-02-26T14:38:03Z
department:
- _id: '15'
doi: 10.1515/qmetro-2016-0002
language:
- iso: eng
publication: Quantum Measurements and Quantum Metrology
publication_identifier:
  issn:
  - 2299-114X
publication_status: published
status: public
title: Quantum enhanced estimation of optical detector efficiencies
type: journal_article
user_id: '49683'
year: '2016'
...
---
_id: '16108'
author:
- first_name: Mihai
  full_name: Vidrighin, Mihai
  last_name: Vidrighin
- first_name: Tim
  full_name: Bartley, Tim
  id: '49683'
  last_name: Bartley
- first_name: Gaia
  full_name: Donati, Gaia
  last_name: Donati
- first_name: Xian-Min
  full_name: Jin, Xian-Min
  last_name: Jin
- first_name: Marco
  full_name: Barbieri, Marco
  last_name: Barbieri
- first_name: W. Steven
  full_name: Kolthammer, W. Steven
  last_name: Kolthammer
- first_name: Animesh
  full_name: Datta, Animesh
  last_name: Datta
- first_name: Ian A.
  full_name: Walmsley, Ian A.
  last_name: Walmsley
citation:
  ama: Vidrighin M, Bartley T, Donati G, et al. Requirements for two-source entanglement
    concentration. <i>Quantum Measurements and Quantum Metrology</i>. 2013. doi:<a
    href="https://doi.org/10.2478/qmetro-2013-0002">10.2478/qmetro-2013-0002</a>
  apa: Vidrighin, M., Bartley, T., Donati, G., Jin, X.-M., Barbieri, M., Kolthammer,
    W. S., … Walmsley, I. A. (2013). Requirements for two-source entanglement concentration.
    <i>Quantum Measurements and Quantum Metrology</i>. <a href="https://doi.org/10.2478/qmetro-2013-0002">https://doi.org/10.2478/qmetro-2013-0002</a>
  bibtex: '@article{Vidrighin_Bartley_Donati_Jin_Barbieri_Kolthammer_Datta_Walmsley_2013,
    title={Requirements for two-source entanglement concentration}, DOI={<a href="https://doi.org/10.2478/qmetro-2013-0002">10.2478/qmetro-2013-0002</a>},
    journal={Quantum Measurements and Quantum Metrology}, author={Vidrighin, Mihai
    and Bartley, Tim and Donati, Gaia and Jin, Xian-Min and Barbieri, Marco and Kolthammer,
    W. Steven and Datta, Animesh and Walmsley, Ian A.}, year={2013} }'
  chicago: Vidrighin, Mihai, Tim Bartley, Gaia Donati, Xian-Min Jin, Marco Barbieri,
    W. Steven Kolthammer, Animesh Datta, and Ian A. Walmsley. “Requirements for Two-Source
    Entanglement Concentration.” <i>Quantum Measurements and Quantum Metrology</i>,
    2013. <a href="https://doi.org/10.2478/qmetro-2013-0002">https://doi.org/10.2478/qmetro-2013-0002</a>.
  ieee: M. Vidrighin <i>et al.</i>, “Requirements for two-source entanglement concentration,”
    <i>Quantum Measurements and Quantum Metrology</i>, 2013.
  mla: Vidrighin, Mihai, et al. “Requirements for Two-Source Entanglement Concentration.”
    <i>Quantum Measurements and Quantum Metrology</i>, 2013, doi:<a href="https://doi.org/10.2478/qmetro-2013-0002">10.2478/qmetro-2013-0002</a>.
  short: M. Vidrighin, T. Bartley, G. Donati, X.-M. Jin, M. Barbieri, W.S. Kolthammer,
    A. Datta, I.A. Walmsley, Quantum Measurements and Quantum Metrology (2013).
date_created: 2020-02-26T15:03:56Z
date_updated: 2022-01-06T06:52:43Z
department:
- _id: '15'
doi: 10.2478/qmetro-2013-0002
extern: '1'
language:
- iso: eng
publication: Quantum Measurements and Quantum Metrology
publication_identifier:
  issn:
  - 2299-114X
publication_status: published
status: public
title: Requirements for two-source entanglement concentration
type: journal_article
user_id: '49683'
year: '2013'
...