Tailored two-photon correlation and fair-sampling: a cautionary tale

J Romero, D Giovannini, D S Tasca, S M Barnett, M J Padgett

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We demonstrate an experimental test of the Clauser–Horne– Shimony–Holt (CHSH) Bell inequality which seemingly exhibits correlations beyond the limits imposed by quantum mechanics. Inspired by the idea of Fourier synthesis, we design analysers that measure specific superpositions of orbital angular momentum (OAM) states, such that when one analyser is rotated with respect to the other, the resulting coincidence curves are similar to a square-wave. Calculating the CHSH Bell parameter, S, from these curves result to values beyond the Tsirelson bound of . We obtain S = 3.99 ± 0.02, implying almost perfect nonlocal Popescu–Rohrlich correlations. The 'super-quantum' values of S is only possible in our experiment because our experiment, subtly, does not comply with fair-sampling. The way our Bell test fails fair-sampling is not immediately obvious and requires knowledge of the states being measured. Our experiment highlights the caution needed in Bell-type experiments based on measurements within high-dimensional state spaces such as that of OAM, especially in the advent of device-independent quantum protocols.

LanguageEnglish
Article number083047
Number of pages11
JournalNew Journal of Physics
Volume15
Issue number8
DOIs
Publication statusPublished - 2013

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bells
sampling
photons
angular momentum
orbitals
square waves
curves
quantum mechanics
synthesis

Keywords

  • Clauser–Horne– Shimony–Holt (CHSH)
  • Fourier synthesis
  • orbital angular momentum (OAM) states
  • CHSH Bell experiments

Cite this

Romero, J., Giovannini, D., Tasca, D. S., Barnett, S. M., & Padgett, M. J. (2013). Tailored two-photon correlation and fair-sampling: a cautionary tale. New Journal of Physics, 15(8), [083047]. https://doi.org/10.1088/1367-2630/15/8/083047
Romero, J ; Giovannini, D ; Tasca, D S ; Barnett, S M ; Padgett, M J. / Tailored two-photon correlation and fair-sampling : a cautionary tale. In: New Journal of Physics. 2013 ; Vol. 15, No. 8.
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Romero, J, Giovannini, D, Tasca, DS, Barnett, SM & Padgett, MJ 2013, 'Tailored two-photon correlation and fair-sampling: a cautionary tale' New Journal of Physics, vol. 15, no. 8, 083047. https://doi.org/10.1088/1367-2630/15/8/083047

Tailored two-photon correlation and fair-sampling : a cautionary tale. / Romero, J; Giovannini, D; Tasca, D S; Barnett, S M; Padgett, M J.

In: New Journal of Physics, Vol. 15, No. 8, 083047, 2013.

Research output: Contribution to journalArticle

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