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This paper is aimed to dissociate nonlocality from quantum theory. We demonstrate that the tests on violation of the Bell type inequalities are simply statistical tests of local incompatibility of observables. In fact, these are tests on…

Quantum Physics · Physics 2021-01-01 Andrei Khrennikov

The relation between entanglement and nonlocality is discussed in the case of multipartite quantum systems. We show that, for any number of parties, there exist genuinely multipartite entangled states which admit a fully local hidden…

Quantum Physics · Physics 2016-04-06 Joseph Bowles , Jérémie Francfort , Mathieu Fillettaz , Flavien Hirsch , Nicolas Brunner

Quantum mechanics predicts that measurements of incompatible observables carry a minimum uncertainty which is independent of technical deficiencies of the measurement apparatus or incomplete knowledge of the state of the system. Nothing yet…

Quantum Physics · Physics 2013-06-14 Davide Girolami , Tommaso Tufarelli , Gerardo Adesso

We consider the problem of a state determination for a two-level quantum system which can be in one of two nonorthogonal mixed states. It is proved that for the two independent identical systems the optimal combined measurement (which…

Quantum Physics · Physics 2007-05-23 A. E. Allahverdyan , D. B. Saakian

Two important ingredients necessary for obtaining Bell nonlocal correlations between two spatially separated parties are an entangled state shared between them and an incompatible set of measurements employed by each of them. We focus on…

Quantum Physics · Physics 2025-05-26 Priya Ghosh , Chirag Srivastava , Swati Choudhary , Ujjwal Sen

It is a well-known fact that measurement incompatibility is a necessary resource to generate nonlocal correlations in usual Bell scenario that typically involves single quantum source. We can provide with some contrasting findings if we…

Quantum Physics · Physics 2025-08-15 Kaushiki Mukherjee , Biswajit Paul

It is shown how to obtain state vectors associated with measurements on the separated subystems of an entangled state, revealing how a single wavefunction encodes a set of statistical measurement outcomes. The result explains why…

Quantum Physics · Physics 2026-05-21 Grgeory D. Scholes

Bell's theorem shows that local measurements on entangled states give rise to correlations incompatible with local hidden variable models. The degree of quantum nonlocality is not maximal though, as there are even more nonlocal theories…

Quantum Physics · Physics 2018-12-26 Cristhiano Duarte , Samuraí Brito , Barbara Amaral , Rafael Chaves

Bell's theorem states that, to simulate the correlations created by measurement on pure entangled quantum states, shared randomness is not enough: some "non-local" resources are required. It has been demonstrated recently that all…

Quantum Physics · Physics 2009-11-10 Nicolas Brunner , Nicolas Gisin , Valerio Scarani

We argue that the conclusion of Bell theorem, namely, that there must be spatial non-local correlations in certain experimental situations, does not apply to typical individual measurements performed on entangled EPR pairs. Our claim is…

General Physics · Physics 2015-10-22 Victor Romero-Rochin

It is shown that the Bell inequalities are closely related to the triangle inequalities involving distance functions amongst pairs of random variables with values $\left\{ 0,1\right\} $. A hidden variables model may be defined as a mapping…

Quantum Physics · Physics 2016-09-28 Emilio Santos

We simulate correlation measurements of entangled photons numerically. The model employed is strictly local. The correlation is determined by its classical expression with one decisive difference: we sum up coincidences for each pair…

Quantum Physics · Physics 2007-05-23 W. A. Hofer

Incompatible measurements, i.e., measurements that cannot be simultaneously performed, are necessary to observe nonlocal correlations. It is natural to ask, e.g., how incompatible the measurements have to be to achieve a certain violation…

Quantum Physics · Physics 2021-05-27 Shin-Liang Chen , Nikolai Miklin , Costantino Budroni , Yueh-Nan Chen

Bell's theorem supposedly demonstrates an irreconcilable conflict between quantum mechanics and local, realistic hidden variable theories. Most proofs of Bell's theorem, are based on inequalities. In this paper we present an alternative…

Quantum Physics · Physics 2025-03-10 Andrea Aiello

Quantum mechanics stands in conflict with local realism only in its treatment of separated systems. A modification of quantum mechanics that changes the handling of separated systems is suggested that can reconcile quantum mechanics with…

Quantum Physics · Physics 2014-09-23 Donald A. Graft

Bell's theorem is typically understood as the proof that quantum theory is incompatible with local-hidden-variable models. More generally, we can see the violation of a Bell inequality as witnessing the impossibility of explaining quantum…

According to Bell's theorem, local realism is incompatible with quantum theory. However, it depends on an implied assumption about quantum measurement. We suggest that the assumption might be removed by a detailed quantum analysis of the…

Quantum Physics · Physics 2009-11-13 Ian Percival , Barry Garraway

A problem in quantum information theory is to find the experimental setup that maximizes the nonlocality of correlations with respect to some suitable measure such as the violation of Bell inequalities. The latter has however some…

Quantum Physics · Physics 2016-08-30 Sacha Schwarz , Andre Stefanov , Stefan Wolf , Alberto Montina

The presence of Bell-nonlocality in the correlations arising from measuring spatially-separated systems guarantees that the sets of measurements used are necessarily incompatible. Not all sets of incompatible measurements can however lead…

Quantum Physics · Physics 2025-08-21 Andrés F. Ducuara , Patryk Lipka-Bartosik , Cristian E. Susa , Paul Skrzypczyk

The characterization of a quantum system can be complicated by non-ideal measurement processes. In many systems, the underlying physical measurement is only sensitive to a single fixed state, complementary outcomes are inferred by…

Quantum Physics · Physics 2014-12-24 Kaila C. S. Hall , Daniel K. L. Oi