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Related papers: Covariance Bell inequalities

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Bell's inequalities can be understood in three different ways depending on whether the numbers featuring in the inequalities are interpreted as classical probabilities, classical conditional probabilities, or quantum probabilities. In the…

Quantum Physics · Physics 2020-04-30 Gábor Hofer-Szabó

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

It is shown that Bell's counterfactuals admit joint quasiprobability distributions (i.e. joint distributions exist, but may not be non-negative). A necessary and sufficient condition for the existence among them of a true probability…

Quantum Physics · Physics 2007-05-23 Noam Erez

The observation that violating Bell inequalities with high probability is possible even when the local measurements are randomly chosen, as occurs when local measurements cannot be suitably calibrated or the parties do not share a common…

Quantum Physics · Physics 2013-08-06 Esteban S. Gómez , Gustavo Cañas , Johanna F. Barra , Adán Cabello , Gustavo Lima

It is known that the local bound of a Bell inequality is sensitive to the knowledge of the external observer about the settings statistics. Here we ask how that sensitivity depends on the structure of that knowledge. It turns out that in…

Quantum Physics · Physics 2015-02-20 P. Horodecki , M. Pawlowski , R. Horodecki

We show that correlations inconsistent with any locally causal description can be a generic feature of measurements on entangled quantum states. Specifically, spatially-separated parties who perform local measurements on a…

Quantum Physics · Physics 2016-09-08 Yeong-Cherng Liang , Nicholas Harrigan , Stephen D. Bartlett , Terry Rudolph

Some new Bell inequalities for consecutive measurements are deduced under joint realism assumption, using some perfect correlation property. No locality condition is needed. When the measured system is a macroscopic system, joint realism…

Quantum Physics · Physics 2009-11-13 Ramon Lapiedra

Quantum mechanics imposes limits on the statistics of certain observables. Perhaps the most famous example is the uncertainty principle. Similar trade-offs also exist for the simultaneous violation of multiple Bell inequalities. In the…

We investigate how accidental counts, the detection events not originating from genuine entangled photon pairs, impact the observed violation of Bell inequalities in photonic experiments. These false coincidences become increasingly…

Quantum Physics · Physics 2025-07-29 Piotr Mironowicz , Mohamed Bourennane

Bell inequality violations are often taken as evidence that quantum nonlocality guarantees intrinsic randomness, effectively playing the role of a "dice" at the heart of many device-independent cryptographic protocols. We show that there…

Quantum Physics · Physics 2025-09-11 Ravishankar Ramanathan , Yuan Liu , Stefano Pironio

Local systems may appear to violate Bell's inequalities if they are observed through suitable filters. The nonlocality leading to violation is outside the system and comprises the observer comparing the outcomes of the typical two wing Bell…

Quantum Physics · Physics 2007-05-23 Helmut Dersch

The interpretation of the meaning of Quantum Mechanics has faced controversy since its inception. Bell's inequalities are a touchstone in this controversy. Their observed violation demonstrates that at least one of the hypotheses involved…

Quantum Physics · Physics 2026-03-27 Mónica Agüero , Juliana Bordieu , Alejandro Hnilo , Marcelo Kovalsky , Myriam Nonaka

Bell inequalities are one of the cornerstones of quantum foundations, and fundamental tools for quantum technologies. Recently, the scientific community worldwide has put a lot of effort towards them, which culminated with loophole-free…

Characterizing the set of all Bell inequalities is a notably hard task. An insightful method of solving it in case of Bell correlation inequalities for scenarios with two dichotomic measurements per site - for arbitrary number of parties -…

EPR showed that two particles emitted from a source can be entangled by a shared wavefunction where two non-commuting observables (position, momentum) can be simultaneously real, leading to a contradiction with quantum mechanics (two…

Quantum Physics · Physics 2026-03-12 Mafiz Uddin

Two overlapping bipartite binary input Bell inequalities cannot be simultaneously violated as this would contradict the usual no-signalling principle. This property is known as monogamy of Bell inequality violations and generally Bell…

Quantum Physics · Physics 2018-09-12 Ravishankar Ramanathan , Piotr Mironowicz

We present a formulation of the Bell inequalities using simple correlated photon number states and phase measurements. Such tests generally require binning of the information, and this effect is closely examined. Our proposal opens up the…

Quantum Physics · Physics 2009-11-06 W. J. Munro

The Bell inequality, and its substantial experimental violation, offers a seminal paradigm for showing that the world is not in fact locally realistic. Here, going beyond the scope of Bell's inequality on physical states, we show that…

Quantum Physics · Physics 2020-01-22 Shih-Hsuan Chen , He Lu , Qi-Chao Sun , Qiang Zhang , Yu-Ao Chen , Che-Ming Li

We present a method to derive Bell monogamy relations by connecting the complementarity principle with quantum non-locality. The resulting monogamy relations are stronger than those obtained from the no-signaling principle alone. In many…

Quantum Physics · Physics 2013-05-29 P. Kurzynski , T. Paterek , R. Ramanathan , W. Laskowski , D. Kaszlikowski

By assuming a deterministic evolution of quantum systems and taking realism into account, we carefully build a hidden variable theory for Quantum Mechanics based on the notion of ontological states proposed by 't Hooft. We view these…

Quantum Physics · Physics 2017-12-04 Natalia Sánchez-Kuntz , Eduardo Nahmad-Achar