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No-hidden-variables proof for two spin-1/2 particles preselected and postselected in unentangled states

Adan Cabello
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Abstract

It is a well-known fact that all the statistical predictions of quantum mechanics on the state of any physical system represented by a two-dimensional Hilbert space can always be duplicated by a noncontextual hidden-variables model. In this paper, I show that, in some cases, when we consider an additional independent (unentangled) two-dimensional system, the quantum description of the resulting composite system cannot be reproduced using noncontextual hidden variables. In particular, a no-hidden-variables proof is presented for two individual spin-1/2 particles preselected in an uncorrelated state AB and postselected in another uncorrelated state aB, B being the same state for the second particle in both preselection and postselection.

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Adan Cabello. 1997-06-06. No-hidden-variables proof for two spin-1/2 particles preselected and postselected in unentangled states. https://doi.org/10.1103/physreva.55.4109

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