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Bell inequalities reveal the fundamentally nonlocal character of quantum mechanics. In this regard, one of the interesting problems is to explore all possible Bell inequalities that demonstrate a gap between local and nonlocal quantum…

Quantum Physics · Physics 2026-02-10 Palash Pandya , Shubhayan Sarkar , Remigiusz Augusiak

Quantum theory allows for correlations between the outcomes of distant measurements that are inconsistent with any locally causal theory, as demonstrated by the violation of a Bell inequality. Typical demonstrations of these correlations…

Quantum Physics · Physics 2012-02-08 Joel J. Wallman , Stephen D. Bartlett

The Bell inequality is thought to be a common constraint shared by all models of local hidden variables that aim to describe the entangled states of two qubits. Since the inequality is violated by the quantum mechanical description of these…

General Physics · Physics 2020-08-05 David H. Oaknin

Bell nonlocality plays a fundamental role in quantum theory. Numerous tests of the Bell inequality have been reported since the ground-breaking discovery of the Bell theorem.Up to now, however, most discussions of the Bell scenario have…

Quantum Physics · Physics 2018-11-08 Meng-Jun Hu , Zhi-Yuan Zhou , Xiao-Min Hu , Chuan-Feng Li , Guang-Can Guo , Yong-Sheng Zhang

We investigate the violation of local realism in Bell tests involving homodyne measurements performed on multimode continuous-variable states. By binning the measurement outcomes in an appropriate way, we prove that the Mermin-Klyshko…

Quantum Physics · Physics 2009-11-13 Antonio Acín , Nicolas J. Cerf , Alessandro Ferraro , Julien Niset

We show that bipartite Bell inequalities based on the Einstein-Podolsky-Rosen criterion for elements of reality and derived from the properties of some hyperentangled states allow feasible experimental verifications of the fact that quantum…

Quantum Physics · Physics 2009-07-28 Adan Cabello

Based on a geometrical argument introduced by Zukowski, a new multisetting Bell inequality is derived, for the scenario in which many parties make measurements on two-level systems. This generalizes and unifies some previous results.…

Quantum Physics · Physics 2009-11-13 Koji Nagata , Wieslaw Laskowski , Tomasz Paterek

We show that a violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality can be demonstrated in a certain kind of Bell experiment for all bipartite entangled states. Our protocol allows local filtering measurements and involves shared…

Quantum Physics · Physics 2008-03-06 Lluis Masanes , Yeong-Cherng Liang , Andrew C. Doherty

We investigate the scenario where spatially separated parties perform measurements in randomly chosen bases on an N-partite Greenberger-Horne-Zeilinger state. We show that without any alignment of the measurements, the observers will obtain…

Quantum Physics · Physics 2015-03-17 Joel J. Wallman , Yeong-Cherng Liang , Stephen D. Bartlett

We compare entanglement with quantum nonlocality employing a geometric structure of the state space of bipartite qudits. Central object is a regular simplex spanned by generalized Bell states. The Collins-Gisin-Linden-Massar-Popescu-Bell…

Quantum Physics · Physics 2015-03-13 Christoph Spengler , Marcus Huber , Beatrix C. Hiesmayr

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

We propose to detect quantum entanglement by a condition of local measurments. We find that this condition can detect efficiently the pure entangled states for both discrete and continuous variable systems. It does not depend on…

Quantum Physics · Physics 2015-05-30 Qing Xie , X. -X. Wu , X. -M. Ding , W. -L. Yang , R. -H. Yue , H. Fan

The violation of Bell inequalities where both detection and locality loopholes are closed is crucial for device independent assessments of quantum information. While of technological nature, the simultaneous closing of both loopholes still…

Quantum Physics · Physics 2015-06-17 Colin Teo , Jiří Minář , Daniel Cavalcanti , Valerio Scarani

The correspondence principle suggests that quantum systems grow classical when large. Classical systems cannot violate Bell inequalities. Yet agents given substantial control can violate Bell inequalities proven for large-scale systems. We…

Quantum Physics · Physics 2021-02-10 Adam Bene Watts , Nicole Yunger Halpern , Aram Harrow

The detection of nonlocal correlations in a Bell experiment implies almost by definition some intrinsic randomness in the measurement outcomes. For given correlations, or for a given Bell violation, the amount of randomness predicted by…

Quantum Physics · Physics 2018-08-20 Erik Woodhead , Boris Bourdoncle , Antonio Acín

Network Bell experiments give rise to a form of quantum nonlocality that conceptually goes beyond Bell's theorem. We investigate here the simplest network, known as the bilocality scenario. We depart from the typical use of the Bell State…

Quantum Physics · Physics 2021-06-04 Armin Tavakoli , Nicolas Gisin , Cyril Branciard

We analyze and compare the mathematical formulations of the criterion for separability for bipartite density matrices and the Bell inequalities. We show that a violation of a Bell inequality can formally be expressed as a witness for…

Quantum Physics · Physics 2009-10-31 Barbara M. Terhal

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

Bell inequalities define experimentally observable quantities to detect non-locality. In general, they involve correlation functions of all the parties. Unfortunately, these measurements are hard to implement for systems consisting of many…

Quantum Physics · Physics 2014-07-14 J. Tura , R. Augusiak , A. B. Sainz , T. Vértesi , M. Lewenstein , A. Acín

Violation of local realism via Bell inequality - a profound and counterintuitive manifestation of quantum theory that conflicts with the prediction of local realism - is viewed to be intimately linked with quantum entanglement. Experimental…