1205.4636 (Marian Kupczynski)

Entanglement and Quantum Nonlocality Demystified    [PDF]

Marian Kupczynski

Quantum nonlocality is presented often as the most remarkable and inexplicable phenomenon known to modern science which was confirmed in the experiments proving the violation of Bell Inequalities (BI). It has been known already for a long time that the probabilistic models used to prove BI for spin polarization correlation experiments (SPCE) are incompatible with the experimental protocols of SPCE. In particular these models use a common probability space together with joint probability distributions for various incompatible coincidence experiments and/or conditional independence (Bell's locality). Strangely enough these results are not known or simply neglected. Therefore so called Bell's or quantum nonlocality has nothing to do with the common notion of the non-locality and it should be rather called quantum non-Kolmogorovness or quantum contextuality. We quickly explain the true meaning of various Bell's locality assumptions and show that if local variables describing the measuring instruments are correctly taken into consideration then BI can no longer be proven. In order to demystify even further the entanglement and quantum long range correlations we give an example of a macroscopic entangled "two qubit state". Namely we show that one can prepare two macroscopic systems in such a way that simple realizable local experiments on these systems violate BI. Of course we do not question the usefulness of the long range correlations characterizing the entangled physical systems in the domain of Quantum Information. However one should not forget that the anti-correlations cannot be perfect, that the wave function should not be treated as an attribute of the individual quantum system which can be change instantaneously and that the unperformed experiments have no results.

View original: http://arxiv.org/abs/1205.4636