Leggett-Garg Inequalities

@article{Emary2013LeggettGargI,
  title={Leggett-Garg Inequalities},
  author={Clive Emary and Neill Lambert and Franco Nori},
  journal={arXiv: Quantum Physics},
  year={2013}
}
In contrast to the spatial Bell's inequalities, which probe entanglement between spatially-separated systems, the Leggett-Garg inequalities test the correlations of a single system measured at different times. Violation of a genuine Leggett-Garg test implies either the absence of a realistic description of the system or the impossibility of measuring the system without disturbing it. Quantum mechanics violates the inequalities on both accounts and the original motivation for these inequalities… 
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