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arXiv · 1106.4481

Experimental non-classicality of an indivisible quantum system

Radek Lapkiewicz·Peizhe Li·Christoph Schaeff·Nathan K. Langford·Sven Ramelow·Marcin Wiesniak·Anton Zeilinger
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Abstract

Quantum theory demands that, in contrast to classical physics, not all properties can be simultaneously well defined. The Heisenberg Uncertainty Principle is a manifestation of this fact. Another important corollary arises that there can be no joint probability distribution describing the outcomes of all possible measurements, allowing a quantum system to be classically understood. We provide the first experimental evidence that even for a single three-state system, a qutrit, no such classical model can exist that correctly describes the results of a simple set of pairwise compatible measurements. Not only is a single qutrit the simplest system in which such a contradiction is possible, but, even more importantly, the contradiction cannot result from entanglement, because such a system is indivisible, and it does not even allow the concept of entanglement between subsystems.

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Radek Lapkiewicz, Peizhe Li, Christoph Schaeff, Nathan K. Langford, Sven Ramelow, Marcin Wiesniak, Anton Zeilinger. 2011-06-22. Experimental non-classicality of an indivisible quantum system. https://doi.org/10.1038/nature10119

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