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Contextual situations are those in which seemingly "the same" random variable changes its identity depending on the conditions under which it is recorded. Such a change of identity is observed whenever the assumption that the variable is…

Quantum Physics · Physics 2015-06-19 Ehtibar N. Dzhafarov , Janne V. Kujala

Two notions of nonclassicality that have been investigated intensively are: (i) negativity, that is, the need to posit negative values when representing quantum states by quasiprobability distributions such as the Wigner representation, and…

Quantum Physics · Physics 2008-07-07 Robert W. Spekkens

We present a formal theory of contextuality for a set of random variables grouped into different subsets (contexts) corresponding to different, mutually incompatible conditions. Within each context the random variables are jointly…

Quantum Physics · Physics 2015-09-01 Ehtibar N. Dzhafarov , Janne V. Kujala , Jan-Åke Larsson

Contextuality is one way of capturing the non-classicality of quantum theory. The contextual nature of a theory is often witnessed via the violation of non-contextuality inequalities---certain linear inequalities involving probabilities of…

Quantum Physics · Physics 2020-07-08 Kishor Bharti , Atul Singh Arora , Leong Chuan Kwek , Jérémie Roland

The use of quantum information in technology promises to supersede the so-called classical devices used nowadays. Understanding what features are inherently non-classical is crucial for reaching better-than-classical performance. This…

Quantum Physics · Physics 2022-04-20 Pierre-Emmanuel Emeriau

In this paper, following an elementary line of thought which somewhat differs from the usual one, we prove once more that any deterministic theory predictively equivalent to quantum mechanics unavoidably exhibits a contextual character. The…

Quantum Physics · Physics 2009-11-13 GianCarlo Ghirardi , Karl Wienand

This paper has two purposes. One is to demonstrate contextuality analysis of systems of epistemic random variables. The other is to evaluate the performance of a new, hierarchical version of the measure of (non)contextuality introduced in…

Neurons and Cognition · Quantitative Biology 2020-09-04 Víctor H. Cervantes , Ehtibar N. Dzhafarov

In quantum mechanics, not everything that can be observed can be observed simultaneously. Observational data exhibits \emph{contextuality} -- a generalisation of nonlocality -- if the result of an observation is necessarily dependent on…

Quantum Physics · Physics 2026-03-13 Ask Ellingsen

The presence of contextuality in quantum theory was first highlighted by Bell, Kochen and Specker, who discovered that for quantum systems of three or more dimensions, measurements cannot be viewed as revealing pre-existing properties of…

Quantum Physics · Physics 2017-04-07 Andrew W. Simmons , Joel J. Wallman , Hakop Pashayan , Stephen D. Bartlett , Terry Rudolph

We compare two approaches to embedding joint distributions of random variables recorded under different conditions (such as spins of entangled particles for different settings) into the framework of classical, Kolmogorovian probability…

Probability · Mathematics 2015-06-18 Ehtibar N. Dzhafarov , Janne V. Kujala

This is a non-technical introduction into theory of contextuality. More precisely, it presents the basics of a theory of contextuality called Contextuality-by-Default (CbD). One of the main tenets of CbD is that the identity of a random…

Probability · Mathematics 2022-01-13 Ehtibar N. Dzhafarov

In quantum physics there are well-known situations when measurements of the same property in different contexts (under different conditions) have the same probability distribution, but cannot be represented by one and the same random…

Neurons and Cognition · Quantitative Biology 2020-06-02 Irina Basieva , Víctor H. Cervantes , Ehtibar N. Dzhafarov , Andrei Khrennikov

This article gives a probabilistic overview of the widely used method of default probability estimation proposed by K. Pluto and D. Tasche. There are listed detailed assumptions and derivation of the inequality where the probability of…

Risk Management · Quantitative Finance 2024-01-26 Andrius Grigutis

A primary goal in recent research on contextuality has been to extend this concept to cases of inconsistent connectedness, where observables have different distributions in different contexts. This article proposes a solution within the…

Quantum Physics · Physics 2019-06-07 Matt Jones

The Contextuality-by-Default approach to determining and measuring the (non)contextuality of a system of random variables requires that every random variable in the system be represented by an equivalent set of dichotomous random variables.…

Quantum Physics · Physics 2022-01-05 Janne V. Kujala , Ehtibar N. Dzhafarov

The Principle of Complementarity of Probabilities based on of noncommutative probability is introduced.

Quantum Physics · Physics 2011-05-10 Andrei Khrennikov , Sergei Kozyrev

We describe a mathematical language for determining all possible patterns of contextuality in the dependence of stochastic outputs of a system on its deterministic inputs. The central notion is that of all possible couplings for…

Mathematical Physics · Physics 2015-01-27 Ehtibar N. Dzhafarov , Janne V. Kujala

Contextuality (or lack thereof) is a property of systems of random variables. Among the measures of the degree of contextuality, two have played important roles. One of them, Contextual Fraction ($\text{CNTF}$) was proposed within the…

Quantum Physics · Physics 2022-11-07 Víctor H. Cervantes

In this paper, we examined the connection between quantum systems' indistinguishability and signed (or negative) probabilities. We do so by first introducing a measure-theoretic definition of signed probabilities inspired by research in…

Quantum Physics · Physics 2020-07-30 J. Acacio de Barros , Federico Holik

Dzhafarov, Zhang, and Kujala (Phil. Trans. Roy. Soc. A 374, 20150099) reviewed several behavioral data sets imitating the formal design of the quantum-mechanical contextuality experiments. The conclusion was that none of these data sets…

Neurons and Cognition · Quantitative Biology 2016-09-28 Ehtibar N. Dzhafarov , Janne V. Kujala , Victor H. Cervantes , Ru Zhang , Matt Jones