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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

Multipartite Bell-type inequalities are derived for general systems. They involve up to eight observables with arbitrary spectra on each site. These inequalities are closely related to the algebras of quaternions and octonions.

Quantum Physics · Physics 2009-11-13 E. Shchukin , W. Vogel

Characterizing trade-offs between simultaneous violations of multiple Bell inequalities in a large network of qubits is computationally demanding. We propose a graph-theoretic approach to efficiently produce Bell monogamy relations in…

Bell inequalities play a central role in the study of quantum non-locality and entanglement, with many applications in quantum information. Despite the huge literature on Bell inequalities, it is not easy to find a clear conceptual answer…

Quantum Physics · Physics 2012-06-21 Samson Abramsky , Lucien Hardy

We prove a set of inequalities that interpolate the Cauchy-Schwarz inequality and the triangle inequality. Every nondecreasing, convex function with a concave derivative induces such an inequality. They hold in any metric space that…

Metric Geometry · Mathematics 2025-01-06 Christof Schötz

We discuss general Bell inequalities for bipartite and multipartite systems, emphasizing the connection with convex geometry on the mathematical side, and the communication aspects on the physical side. Known results on families of…

Quantum Physics · Physics 2007-05-23 Reinhard F. Werner , Michael M. Wolf

The problem of characterizing classical and quantum correlations in networks is considered. Contrary to the usual Bell scenario, where distant observers share a physical system emitted by one common source, a network features several…

Quantum Physics · Physics 2021-04-21 Armin Tavakoli , Marc-Olivier Renou , Nicolas Gisin , Nicolas Brunner

So far, various Bell type inequalities have been introduced to test the local realism in tripartite systems. In this article we consider a tripartite system with two measurements in each side and two outputs for each measurement. Then we…

Quantum Physics · Physics 2011-06-28 Fatemeh Shirdel , Hossein Movahhedian

The Bell inequalities in three and four correlations are re-derived in general forms showing that three and four data sets, respectively, identically satisfy them regardless of whether they are random, deterministic, measured, predicted, or…

Quantum Physics · Physics 2020-06-24 Louis Sica

We present unified approach to different recent entanglement criteria. Although they were developed in different ways, we show that they are all applications of a more general principle given by the Cauchy-Schwarz inequality. We explain…

Quantum Physics · Physics 2015-06-19 Sabine Wölk , Marcus Huber , Otfried Gühne

We investigate the Bell inequalities derived from the graph states with violations detectable even with the presence of noises, which generalizes the idea of error-correcting Bell inequalities [Phys. Rev. Lett. 101, 080501 (2008)]. Firstly…

Quantum Physics · Physics 2009-03-20 Qing Chen , Sixia Yu , C. H. Oh

The Bell-CHSH (Clauser-Horne-Shimony-Holt) inequality in the vacuum state of a relativistic scalar quantum field is analyzed. Using Weyl operators built with smeared fields localized in the Rindler wedges, the Bell-CHSH inequality is…

High Energy Physics - Theory · Physics 2024-09-16 Philipe De Fabritiis , Marcelo S. Guimaraes , Itzhak Roditi , Silvio P. Sorella

We present a Bell-type inequality for four-qubit systems. Using the inequality we investigate quantum nonlocality of a generic family of states $\left|G_{abcd}\right >$ [Phys. Rev. A 65, 052112 (2002)] and several canonical four-qubit…

Quantum Physics · Physics 2017-06-07 Dong Ding , Fengli Yan , Ting Gao

Quantum nonlocality, one of the most important features of quantum mechanics, is normally connected in experiments with the violation of Bell-Clauser-Horne (Bell-CH) inequalities. We propose effective methods for the rearrangement and…

Quantum Physics · Physics 2021-06-08 Chen Qian , Yang-Guang Yang , Cong-Feng Qiao , Qun Wang

We develop a novel approach to Bell inequalities based on a constraint that the correlations exhibited by local realistic theories must satisfy. This is used to construct a family of Bell inequalities for bipartite quantum systems of…

Quantum Physics · Physics 2009-11-07 D. Collins , N. Gisin , N. Linden , S. Massar , S. Popescu

We consider a subclass of bipartite CHSH-type Bell inequalities. We investigate operations, which leave their Tsirelson bound invariant, but change their classical bound. The optimal observables are unaffected except for a relative rotation…

Quantum Physics · Physics 2014-10-10 Michael Epping , Hermann Kampermann , Dagmar Bruß

We introduce Bell inequalities based on covariance, one of the most common measures of correlation. Explicit examples are discussed, and violations in quantum theory are demonstrated. A crucial feature of these covariance Bell inequalities…

Quantum Physics · Physics 2017-12-27 Victor Pozsgay , Flavien Hirsch , Cyril Branciard , Nicolas Brunner

The consistency test and error estimation for the data concerning recently reported violation of Bell inequality for Josephson phase qubits are presented in details. It is pointed out that the deviation of the Bell signal from the classical…

Quantum Physics · Physics 2009-11-23 Robert Alicki

We present an analysis of the structure of Bell inequalities, mainly for the case of N qubits with two observables each. We show that these inequalities are related to Hadamard matrices and define Bell polynomials (in one variable) as an…

Quantum Physics · Physics 2007-05-23 Guenter Schachner

We introduce a set of Bell inequalities for a three-qubit system. Each inequality within this set is violated by all generalized GHZ states. More entangled a generalized GHZ state is, more will be the violation. This establishes a relation…

Quantum Physics · Physics 2017-11-02 Arpan Das , Chandan Datta , Pankaj Agrawal