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arXiv · 1505.06825

Experimental generalized contextuality with single-photon qubits

Xiang Zhan·Eric G. Cavalcanti·Jian Li·Zhihao Bian·Yongsheng Zhang·Howard M. Wiseman·Peng Xue
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Abstract

Contextuality is a phenomenon at the heart of the quantum mechanical departure from classical behaviour, and has been recently identified as a resource in quantum computation. Experimental demonstration of contextuality is thus an important goal. The traditional form of contextuality -- as violation of a Kochen-Specker inequality -- requires a quantum system with at least three levels, and the status of the assumption of determinism used in deriving those inequalities has been controversial. By considering `unsharp' observables, Liang, Spekkens and Wiseman (LSW) derived an inequality for generalized noncontextual models that doesn't assume determinism, and applies already to a qubit. We experimentally implement the LSW test using the polarization states of a heralded single photon and three unsharp binary measurements. We violate the LSW inequality by more than 16 standard deviations, thus showing that our results cannot be reproduced by a noncontextual subset of quantum theory.

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Xiang Zhan, Eric G. Cavalcanti, Jian Li, Zhihao Bian, Yongsheng Zhang, Howard M. Wiseman, Peng Xue. 2017-07-21. Experimental generalized contextuality with single-photon qubits. https://doi.org/10.1364/optica.4.000966

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