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Y. Hasegawa, R. Loidl, M. Baron, G. Badurek, H. Rauch:
"Quantum contextuality in neutron interferometer experiments";
Physica B: Condensed Matter, 385-386 (2006), 1377 - 1380.

Non-local correlations between sufficiently separated subsystems have been extensively discussed. Such a non-locality can be
interpreted as a consequence of the correlation between commuting observables. A more general concept, i.e., contextuality, compared to
non-locality can be introduced to describe striking phenomena predicted by quantum theory. As the first example, we report a neutron
interferometer experiment, where the spin and the path degrees of freedom are used to exhibit the clear violation of a Bell-like inequality.
Other aspects of the quantum contextuality is presented, e.g., a flavor of Kochen-Specker-like contradiction in neutron optical
experiments, in addition to the quantum state tomography of the Bell-states which are used in the experiments.