A Bell Experiment under Strict Einstein Locality Conditions

Abstract

After Bell in 1965^[1] showed that local hidden parameters would contradict the predictions of quantum physics for systems of entangled particle pairs, a number of experimental tests have been performed^[2,3,4]. All recent experiments confirm the predictions of quantum theory with increasing experimental accuracy. Yet, from a strictly logical point of view, they don’t succeed in ruling out a local realistic explanation completely because there are two essential loopholes The first^[5] builds on the fact that real experiments so far do not detect all particle pairs created, and that in principle the whole set of all pairs could still behave according to local realistic theories contrary to the experimental result. Bell early expressed his view that the more important loophole was the static character of all existing experiments.^[6] The only experiment up to now, in which the directions of polarization analysis were switched while the particles were in flight, was performed by Aspect et al.^[3] However, they used periodic switching, which was perfectly predictable. Thus communication between analyzers and particles slower than the speed of light^[7] could in principle have explained their results.