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In the case of bipartite two qubits systems, we derive the analytical expression of bound of Bell operator for any given pure state. Our result not only manifest some properties of Bell inequality, for example which may be violated by any…

Quantum Physics · Physics 2011-02-02 Yang Xiang

We present new bell inequalities for arbitrary dimensional bipartite quantum systems. The maximal violation of the inequalities is computed. The Bell inequality is capable of detecting quantum entanglement of both pure and mixed quantum…

Quantum Physics · Physics 2015-05-27 Ming Li , Shao-Ming Fei , Xianqing Li-Jost

We have determined numerically the maximum quantum violation of over 100 tight bipartite Bell inequalities with two-outcome measurements by each party on systems of up to four dimensional Hilbert spaces. We have found several cases,…

Quantum Physics · Physics 2009-11-13 K. F. Pál , T. Vértesi

We computationally investigate the complete polytope of Bell inequalities for 2 particles with small numbers of possible measurements and outcomes. Our approach is limited by Pitowsky's connection of this problem to the computationally hard…

Quantum Physics · Physics 2023-03-23 Daniel Collins , Nicolas Gisin

We consider quantum systems composed of $N$ qubits, and the family of all Bell's correlation inequalities for two two-valued measurements per site. We show that if a $N$-qubit state $\rho$ violates any of these inequalities, then it is at…

Quantum Physics · Physics 2009-11-07 A. Acin , V. Scarani , M. M. Wolf

A suitable generalized measurement described by a 4-element positive operator-valued measure (POVM) on each particle of a two-qubit system in the singlet state is, from the point of view of Einstein, Podolsky, and Rosen's (EPR's) criterion…

Quantum Physics · Physics 2009-07-28 Adan Cabello

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

Bell inequalities for number measurements are derived via the observation that the bits of the number indexing a number state are proper qubits. Violations of these inequalities are obtained from the output state of the nondegenerate…

Quantum Physics · Physics 2022-03-16 Jan-Åke Larsson

In this paper we obtain violations of general bipartite Bell inequalities of order $\frac{\sqrt{n}}{\log n}$ with $n$ inputs, $n$ outputs and $n$-dimensional Hilbert spaces. Moreover, we construct explicitly, up to a random choice of signs,…

Quantum Physics · Physics 2011-08-30 Marius Junge , Carlos Palazuelos

The relation between Bell inequalities with two two-outcome measurements per site and distillability is analyzed in systems of an arbitrary number of quantum bits. We observe that the violation of any of these inequalities by a quantum…

Quantum Physics · Physics 2009-11-07 Antonio Acin , Valerio Scarani , Michael M. Wolf

First, we present a Bell type inequality for n qubits, assuming that m out of the n qubits are independent. Quantum mechanics violates this inequality by a ratio that increases exponentially with m. Hence an experiment on n qubits violating…

Quantum Physics · Physics 2009-10-31 N. Gisin , H. Bechmann-Pasquinucci

Recently, V\'{e}rtesi and Bene [Phys. Rev. A. {\bf 82}, 062115 (2010)] derived a two-qubit Bell inequality, $I_{CH3}$, which they show to be maximally violated only when more general positive operator valued measures (POVMs) are used…

Quantum Physics · Physics 2015-06-05 J. F. Barra , E. S. Gómez , G. Cañas , W. A. T. Nogueira , L. Neves , G. Lima

Here we propose an implementation of all possible Positive Operator Value Measures (POVMs) of two-photon polarization states. POVMs are the most general class of quantum measurements. Our setup requires linear optics, Bell State…

Quantum Physics · Physics 2009-11-11 S. E. Ahnert , M. C. Payne

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

We discuss the connection between the incompatibility of quantum measurements, as captured by the notion of joint measurability, and the violation of Bell inequalities. Specifically, we present explicitly a given a set of non jointly…

Quantum Physics · Physics 2018-02-02 Flavien Hirsch , Marco Túlio Quintino , Nicolas Brunner

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

In this work we show that bipartite quantum states with local Hilbert space dimension n can violate a Bell inequality by a factor of order $\sqrt{n}$ (up to a logarithmic factor) when observables with n possible outcomes are used. A central…

Quantum Physics · Physics 2015-05-14 M. Junge , C. Palazuelos , D. Perez-Garcia , I. Villanueva , M. M. Wolf

In the present article, based on the formalism introduced in [Loubenets, J. Math. Phys. 53, 022201 (2012)], we derive for a pure bipartite quantum state a new upper bound on its maximal violation of general Bell inequalities. This new bound…

Quantum Physics · Physics 2021-10-19 Elena R. Loubenets , Min Namkung

Bipartite temporal Bell inequalities are similar to the usual Bell inequalities except that, instead of changing the direction of the polariser at each measurement, one changes the time at which the measurement is being performed. By doing…

Quantum Physics · Physics 2020-11-18 Kenta Ando , Vincent Vennin

Bell nonlocality is a fundamental phenomenon of quantum physics as well as an essential resource for various tasks in quantum information processing. It is known that for the observation of nonlocality the measurements on a quantum system…

Quantum Physics · Physics 2025-07-16 Martin Plávala , Otfried Gühne , Marco Túlio Quintino
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