Preparation Contextuality Powers Parity-Oblivious Multiplexing

Robert W. Spekkens, D. H. Buzacott, A. J. Keehn, Ben Toner, and G. J. Pryde
Phys. Rev. Lett. 102, 010401 – Published 5 January 2009
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Abstract

In a noncontextual hidden variable model of quantum theory, hidden variables determine the outcomes of every measurement in a manner that is independent of how the measurement is implemented. Using a generalization of this notion to arbitrary operational theories and to preparation procedures, we demonstrate that a particular two-party information-processing task, “parity-oblivious multiplexing,” is powered by contextuality in the sense that there is a limit to how well any theory described by a noncontextual hidden variable model can perform. This bound constitutes a “noncontextuality inequality” that is violated by quantum theory. We report an experimental violation of this inequality in good agreement with the quantum predictions. The experimental results also provide the first demonstration of 2-to-1 and 3-to-1 quantum random access codes.

  • Figure
  • Received 12 May 2008

DOI:https://doi.org/10.1103/PhysRevLett.102.010401

©2009 American Physical Society

Authors & Affiliations

Robert W. Spekkens1, D. H. Buzacott2,3, A. J. Keehn2,3, Ben Toner4, and G. J. Pryde2,3

  • 1DAMTP, University of Cambridge, Cambridge, CB3 0WA, United Kingdom
  • 2Centre for Quantum Computer Technology, Griffith University, Brisbane 4111, Australia
  • 3Centre for Quantum Dynamics, Griffith University, Brisbane 4111, Australia
  • 4Centrum voor Wiskunde en Informatica, Kruislaan 413, 1098 SJ Amsterdam, The Netherlands

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Issue

Vol. 102, Iss. 1 — 9 January 2009

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