Entanglement, Measurement and Quantum Paradoxes

Gerardo Adesso, Marco Piani

Jorma Jormakka

The hidden variable solution to the EPR paradox proposes that correlation of measurements of entangled particles is due to variables that get decided when the entangled particles get created. It is shown that the correlation of spin measurements in Bell's form of the EPR paradox can be explained as deriving from spin of the entangled particles in the x-direction. This spin parameter is not hidden as it is included in the standard quantum mechanical formulation.

Marco Piani, Gerardo Adesso

Adel Sohbi, Jaewan Kim

We present a logical type of proof of contextuality for a two-qubit state. We formulate a paradox that cannot be used by a two-qubit system with local measurements to test contextuality while it is possible by using entanglement measurements. With our scheme we achieve ${p}_{\mathrm{Hardy}}\ensuremath{\approx}0.167$. Our approach uses graph theory and the exclusivity principle to give an interpretation of a logical type of proof of quantum correlations. We review the Hardy paradox and find a connection to the Klyachko-Can-Binicio\ifmmode \breve{g}\else \u{g}\fi{}lu-Shumovsky inequality. We apply the same method to build a paradox based on the Clauser-Horne-Shimony-Holt inequality.

N.O. Chudak, O. S. Potiienko, I. V. Sharph +1 more

Five objections to the conventional arguments underlying the EPR \enquote{paradox} are presented. It is shown that for entangled subsystems the formation of the post-measurement state necessarily involves local interactions affecting both subsystems, contradicting standard EPR assumptions. Correlations between measurements by remote apparatuses are shown to be consistent with relativistic principles. For entangled eigenstates of total momentum or total spin, eliminating redundant degrees of freedom in analogy with generalized Hamiltonian dynamics prevents the emergence of the EPR \enquote{paradox}. A different paradox is identified for a quantum charged particle, whose electric field is shown to be determined by potential configurations encoded in the quantum state rather than by actual measurement events.

A. J. Leggett