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Euclidean volume ratios between quantum states with positive partial transpose and all quantum states in bipartite systems are investigated. These ratios allow a quantitative exploration of the typicality of entanglement and of its…

Quantum Physics · Physics 2022-07-07 A. Sauer , J. Z. Bernád , H. J. Moreno , G. Alber

Quantum measurements on a two-level system can have more than two independent outcomes, and in this case, the measurement cannot be projective. Measurements of this general type are essential to an operational approach to quantum theory,…

Nonlocality of two-mode states of light is addressed by means of CHSH inequality based on displaced on/off photodetection. Effects due to non-unit quantum efficiency and nonzero dark counts are taken into account. Nonlocality of both…

Quantum Physics · Physics 2009-11-11 Carmen Invernizzi , Stefano Olivares , Matteo G. A. Paris , Konrad Banaszek

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

To obtain Bell statistics from hybrid systems composed of finite- and infinite-dimensional systems, we propose a hybrid measurement scheme, in which the continuous mode is measured using the generalized pseudospin operators, while the…

Quantum Physics · Physics 2025-02-26 Pritam Halder , Ratul Banerjee , Saptarshi Roy , Aditi Sen De

Hardy-type arguments manifest Bell nonlocality in one of the simplest possible ways. Except for demonstrating nonclassical signature of entangled states in question, they can also serve for device-independent self-testing of states, as…

Quantum Physics · Physics 2021-06-30 Ashutosh Rai , Matej Pivoluska , Martin Plesch , Souradeep Sasmal , Manik Banik , Sibasish Ghosh

We in this Letter derive analytic formulas of Bell correlations in terms of quantum probability statistics under the assumption of measuring outcome-independence. For a spin-1/2 singlet state we find analytically that the violations of…

Quantum Physics · Physics 2013-04-09 Zhigang Song , J. -Q. Liang , L. -F. Wei

Many typical Bell experiments can be described as follows. A source repeatedly distributes particles among two spacelike separated observers. Each of them makes a measurement, using an observable randomly chosen out of several possible…

Quantum Physics · Physics 2015-01-08 Michael Epping , Hermann Kampermann , Dagmar Bruß

We study nonlocality tests in which each party performs photodetection and homodyne measurements. The results of such measurements are dichotomized and a Clauser-Horne-Shimony-Holt (CHSH) inequality is used. We prove that in this scenario…

Noncommuting observables cannot be simultaneously measured, however, under local hidden variable models, they must simultaneously hold premeasurement values, implying the existence of a joint probability distribution. We study the joint…

Quantum Physics · Physics 2017-05-30 Omar E. Gamel , Graham R. Fleming

The relation between Bell-CHSH violation and factorization of Hilbert space is considered here. That is, a state which is local in the sense of the Bell-CHSH inequality under a certain factorization of the underlying Hilbert space can be…

In this work we aim to analyze the Clauser-Horne-Shimony-Holt CHSH inequality strictly in the context of probability theory. In the course of assembling inequality we have to take care not to produce assumptions a priori, that is,…

Quantum Physics · Physics 2018-05-31 Felipe Andrade Velozo , José A. C. Nogales , Gustavo Figueiredo Araújo

In contrast to the wide-spread opinion that any separable quantum state satisfies every classical probabilistic constraint, we present a simple example where a separable quantum state does not satisfy the original Bell inequality although…

Quantum Physics · Physics 2007-05-23 Elena R. Loubenets

Sufficient conditions for (the non-violation of) the Bell-CHSH inequalities in a mixed state of a two-qubit system are: 1) The linear entropy of the state is not smaller than 0.5, 2) The sum of the conditional linear entropies is…

Quantum Physics · Physics 2009-11-10 Emilio Santos

We show that a pair of massive relativistic spin-1/2 particles prepared in a maximally entangled spin state in general is not capable of maximally violating the Clauser-Horne-Shimony-Holt (CHSH) version of Bell's inequalities without a…

Quantum Physics · Physics 2012-06-12 Pablo L. Saldanha , Vlatko Vedral

Mermin's inequality is the generalization of the Bell-CHSH inequality for three qubit states. The violation of the Mermin inequality guarantees the fact that there exists quantum non-locality either between two or three qubits in a three…

Quantum Physics · Physics 2016-02-09 Satyabrata Adhikari , A. S. Majumdar

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

Device independent protocols based on Bell nonlocality, such as quantum key distribution and randomness generation, must ensure no adversary can have prior knowledge of the measurement outcomes. This requires a measurement independence…

Quantum Physics · Physics 2020-12-08 Michael J. W. Hall , Cyril Branciard

The robustness of Bell's inequality (in CHSH form) violation by entangled state in the simultaneous presence of colored and white noise in the system is considered. A twophoton polarization state is modeled by twoparameter density matrix.…

Quantum Physics · Physics 2008-07-02 Ivan S. Dotsenko , Volodymyr G. Voronov

We give a set of necessary conditions for locality in bipartite systems, which include and generalize known Bell's inequalities. Each condition corresponds to a specific order of the expansion of random variables defined on graphs, in terms…