Violation of Bell's inequality in Josephson phase qubits

@article{Ansmann2009ViolationOB,
  title={Violation of Bell's inequality in Josephson phase qubits},
  author={Markus Ansmann and H. Wang and Radoslaw C. Bialczak and Max Hofheinz and Erik Lucero and Matthew Neeley and Aaron O'Connell and Daniel Thomas Sank and Martin P. Weides and J. Wenner and Andrew N. Cleland and John M. Martinis},
  journal={Nature},
  year={2009},
  volume={461},
  pages={504-506}
}
The measurement process plays an awkward role in quantum mechanics, because measurement forces a system to ‘choose’ between possible outcomes in a fundamentally unpredictable manner. Therefore, hidden classical processes have been considered as possibly predetermining measurement outcomes while preserving their statistical distributions. However, a quantitative measure that can distinguish classically determined correlations from stronger quantum correlations exists in the form of the Bell… 
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