General Bells theorem

[PHY]

A very general Bells theorem without inequalities for two particle states

We consider an entangled two-particle state that is produced from two independent downconversions by the process of entanglement swapping, so that the particles will have never met. We prove a GHZ (Greenberger-Horne-Zeilinger) type theorem, showing that the quantum mechanical perfect correlations for such a state are inconsistent with any deterministic, local, realistic theory. This theorem holds for individual events with no inequalities, for detectors of 100% efficiency. Furthermore, we can show that for certain specific sets of angles such a realistic theory predicts that no events at all can take place, in a complete contradiction to the quantum case. This result holds for arbitrarily small detection efficiencies and is independent of any random sampling hypothesis, and we take it as a refutation of such realistic theories, free of these two: loopholes.

[GVideo]http://video.google.com/videoplay?docid=-636511261806857355&q=calculus[/GVideo]

43 min 1 sec - Sep 3, 2004
Ulm University, Germany