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The worst violation of Bell's inequality for $n$ qbits is of size $2^{\frac{n-1}{2}}$ and it is obtained by a specific operator acting on a specific state. We show, to the contrary, that for a vast majority of Bell operators the worst…

Quantum Physics · Physics 2007-05-23 Itamar Pitowsky

We show that there is a stronger form of bipartite quantum nonlocality in which systems that never interacted are as nonlocal as allowed by no-signaling. For this purpose, we first show that nonlocal boxes, theoretical objects that violate…

Quantum Physics · Physics 2012-11-26 Adan Cabello

We review the status of Bell's inequalities in quantum information, stressing mainly the links with quantum key distribution and distillation of entanglement. We also prove that for all the eavesdropping attacks using one qubit, and for a…

Quantum Physics · Physics 2007-05-23 Antonio Acin , Nicolas Gisin , Lluis Masanes , Valerio Scarani

We demonstrate that it is possible to simulate Bell violations using probabilistic methods. A quantum state corresponding to optical experiments that violate the Bell inequality is generated, demonstrating that these quantum paradoxes can…

Quantum Physics · Physics 2014-04-08 Peter D. Drummond , Bogdan Opanchuk , Laura Rosales-Zárate , Margaret D. Reid

The strength of classical correlations is subject to certain constraints, commonly known as Bell inequalities. Violation of these inequalities is the manifestation of nonlocality---displayed, in particular, by quantum mechanics, meaning…

Quantum Physics · Physics 2015-03-18 R. Augusiak , J. Stasińska , C. Hadley , J. K. Korbicz , M. Lewenstein , A. Acín

The discrepancy between maximally entangled states and maximally non-classical quantum correlations is well-known but still not well understood. We aim to investigate the relation between quantum correlations and entanglement in a family…

Quantum Physics · Physics 2016-03-01 Armin Tavakoli , Stefan Zohren , Marcin Pawlowski

We deduce the non-asymptotical bilateral estimates for moment inequalities for sums of non-negative independent random variables, based on the correspondent estimates for the so-called Bell functions and the Poisson distribution.

Probability · Mathematics 2017-12-27 E. Ostrovsky , L. Sirota

Entropic Bell inequalities witness contextual probability distributions on sets of jointly measurable observables. We find that their violation does not entail a violation of the correlative Bell inequality for certain parameter values.…

Quantum Physics · Physics 2020-11-03 Sabiha Durucan , Alexei Grinbaum

In a Bell test, the set of observed probability distributions complying with the principle of local realism is fully characterized by Bell inequalities. Quantum theory allows for a violation of these inequalities, which is famously regarded…

Quantum Physics · Physics 2022-06-01 Mariami Gachechiladze , Bartłomiej Bąk , Marcin Pawłowski , Nikolai Miklin

The self-testing protocols refer to novel device-independent certification schemes wherein the devices are uncharacterised, and the dimension of the system remains unspecified. The optimal quantum violation of a Bell's inequality…

Quantum Physics · Physics 2024-08-21 Rajdeep Paul , Souradeep Sasmal , A. K. Pan

We present a generalized Bell inequality for two entangled quNits. On one quNit the choice is between two standard von Neumann measurements, whereas for the other quNit there are $N^2$ different binary measurements. These binary…

Quantum Physics · Physics 2007-05-23 H. Bechmann-Pasquinucci , N. Gisin

Bipartite Bell inequalities can be simultaneously violated by two different pairs of observers when weak measurements and signaling is employed. Here we experimentally demonstrate the violation of two simultaneous CHSH inequalities by…

Quantum Physics · Physics 2017-04-10 Matteo Schiavon , Luca Calderaro , Mirko Pittaluga , Giuseppe Vallone , Paolo Villoresi

Cluster states are a new type of multiqubit entangled states with entanglement properties exceptionally well suited for quantum computation. In the present work, we experimentally demonstrate that correlations in a four-qubit linear cluster…

Quantum Physics · Physics 2009-11-11 Philip Walther , Markus Aspelmeyer , Kevin J. Resch , Anton Zeilinger

Bell nonlocality -- the existence of quantum correlations that cannot be explained by classical means -- is certainly one of the most striking features of quantum mechanics. Its range of applications in device-independent protocols is…

Quantum Physics · Physics 2023-12-06 Rafael Santos , Debashis Saha , Flavio Baccari , Remigiusz Augusiak

The standard Bell inequality experiments test for violation of local realism by repeatedly making local measurements on individual copies of an entangled quantum state. Here we investigate the possibility of increasing the violation of a…

Quantum Physics · Physics 2007-05-23 Yeong-Cherng Liang , Andrew C. Doherty

A multipartite quantum state violates a Bell inequality asymptotically if, after jointly processing by general local operations an arbitrarily large number of copies of it, the result violates the inequality. In the bipartite case we show…

Quantum Physics · Physics 2009-11-11 Ll. Masanes

While all bipartite pure entangled states are known to generate correlations violating a Bell inequality, and are therefore nonlocal, the quantitative relation between pure-state entanglement and nonlocality is poorly understood. In fact,…

Quantum Physics · Physics 2018-08-14 Victoria Lipinska , Florian Curchod , Alejandro Máttar , Antonio Acín

Proposals for Bell inequality tests on systems restricted by superselection rules often require operations that are difficult to implement in practice. In this paper, we derive a new Bell inequality, where pairs of states are used to…

Quantum Physics · Physics 2015-05-19 Libby Heaney , Seung-Woo Lee , Dieter Jaksch

When a collection of distant observers share an entangled quantum state, the statistical correlations among their measurements may violate a many-body Bell inequality, demonstrating a non-local behavior. Focusing on the Ising model in a…

Strongly Correlated Electrons · Physics 2019-10-25 Angelo Piga , Albert Aloy , Maciej Lewenstein , Irénée Frérot

We consider the expected violations of Bell inequalities from random pure states. More precisely, we focus on a slightly generalised version of the CGLMP inequality, which concerns Bell experiments of two parties, two measurement options…

Quantum Physics · Physics 2015-08-05 Max R. Atkin , Stefan Zohren