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arXiv · 1604.06419

Bell Correlations in a Bose-Einstein Condensate

Roman Schmied·Jean-Daniel Bancal·Baptiste Allard·Matteo Fadel·Valerio Scarani·Philipp Treutlein·Nicolas Sangouard
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Abstract

Characterizing many-body systems through the quantum correlations between their constituent particles is a major goal of quantum physics. Although entanglement is routinely observed in many systems, we report here the detection of stronger correlations - Bell correlations - between the spins of about 480 atoms in a Bose-Einstein condensate. We derive a Bell correlation witness from a many-particle Bell inequality involving only one- and two-body correlation functions. Our measurement on a spin-squeezed state exceeds the threshold for Bell correlations by 3.8 standard deviations. Our work shows that the strongest possible non-classical correlations are experimentally accessible in many-body systems, and that they can be revealed by collective measurements.

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Roman Schmied, Jean-Daniel Bancal, Baptiste Allard, Matteo Fadel, Valerio Scarani, Philipp Treutlein, Nicolas Sangouard. 2016-04-21. Bell Correlations in a Bose-Einstein Condensate. https://doi.org/10.1126/science.aad8665

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