Bell correlations in a Bose-Einstein condensate.
- Schmied R Quantum Atom Optics Laboratory, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
- Bancal JD Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543. Quantum Optics Theory Group, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
- Allard B Quantum Atom Optics Laboratory, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
- Fadel M Quantum Atom Optics Laboratory, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
- Scarani V Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542.
- Treutlein P Quantum Atom Optics Laboratory, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland. philipp.treutlein@unibas.ch nicolas.sangouard@unibas.ch.
- Sangouard N Quantum Optics Theory Group, Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland. philipp.treutlein@unibas.ch nicolas.sangouard@unibas.ch.
- 2016-04-23
Published in:
- Science (New York, N.Y.). - 2016
English
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 nonclassical correlations are experimentally accessible in many-body systems and that they can be revealed by collective measurements.
- Language
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- English
- Open access status
- green
- Identifiers
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- DOI 10.1126/science.aad8665
- PMID 27102479
- Persistent URL
- https://sonar.ch/global/documents/90489
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