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Related papers: Simple Hardy-like proof of quantum contextuality

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Hardy's nonlocality argument, which establishes incompatibility of quantum theory with local-realism, can also be used to reveal the time-nonlocal feature of quantum states. For spin-1/2 systems, the maximum probability of success of this…

Quantum Physics · Physics 2013-02-22 Sujit K Choudhary , Sandeep K Goyal , Thomas Konrad , Sibasish Ghosh

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

Bell nonlocality and Kochen-Specker contextuality are among the main topics of foundations of quantum theory. Both of them are related to stronger-than-classical correlations, with the former usually referring to spatially separated systems…

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

The widespread claim that violations of Bell inequalities establish the nonlocality of nature is critically reexamined. It is argued that this conclusion is not logically compelled by either the Einstein-Podolsky-Rosen (EPR) argument or…

Quantum Physics · Physics 2026-05-05 Partha Ghose

Unspeakable coherence is a key feature separating quantum and classical physics. Modelled as asymmetry with respect to a continuous transformation generated by a physically relevant observable, such as the Hamiltonian or angular moment,…

Quantum Physics · Physics 2025-12-05 Benjamin Stratton , Chung-Yun Hsieh , Paul Skrzypczyk

Nonlocality can be studied through different approaches, such as Bell's inequalities, and it can be found in numerous quantum states, including GHZ states or graph states. Hardy's paradox, or Hardy-type nonlocality, provides a way to…

Quantum Physics · Physics 2026-01-09 Duc Manh Doan , Hung Q. Nguyen

We discuss quantum non-locality and contextuality using the notion of transition sets. This approach provides a way to obtain a direct logical contradiction with locality/non-contextuality in the EPRB gedanken experiment as well as a clear…

Quantum Physics · Physics 2007-11-19 Hans Westman

We highlight the existence of a joint probability distribution as the common underpinning assumption behind Bell-type, contextuality, and Leggett-Garg-type tests. We then present a procedure to translate contextual scenarios into temporal…

Quantum Physics · Physics 2016-10-13 M. Markiewicz , P. Kurzynski , J. Thompson , S. -Y. Lee , A. Soeda , T. Paterek , D. Kaszlikowski

Contextuality is a key characteristic that separates quantum from classical phenomena and an important tool in understanding the potential advantage of quantum computation. However, when assessing the quantum resources available for quantum…

Quantum Physics · Physics 2026-03-04 Maiyuren Srikumar , Stephen D. Bartlett , Angela Karanjai

The Kochen-Specker (KS) theorem is a fundamental result in quantum foundations that has spawned massive interest since its inception. We present state-independent non-contextuality inequalities with large violations, in particular, we…

Quantum Physics · Physics 2022-12-22 Ravishankar Ramanathan , Yuan Liu , Paweł Horodecki

We establish a strong link between two apparently unrelated topics: the study of conflicting information in the formal framework of valuation algebras, and the phenomena of non-locality and contextuality. In particular, we show that these…

Quantum Physics · Physics 2019-11-12 Samson Abramsky , Giovanni Carù

We give a analytic quantitative relation between Hardy's non-locality and Bell operator. We find that Hardy's non-locality is a sufficient condition for violation of Bell inequality, the upper bound of Hardy's non-locality allowed by…

Quantum Physics · Physics 2015-05-19 Yang Xiang

This article delves into the concept of quantum contextuality, specifically focusing on proofs of the Kochen-Specker theorem obtained by assigning Pauli observables to hypergraph vertices satisfying a given commutation relation. The…

Quantum Physics · Physics 2025-08-27 Axel Muller , Alain Giorgetti

We consider the phenomenon of quantum mechanical contextuality, and specifically parity-based proofs thereof. Mermin's square and star are representative examples. Part of the information invoked in such contextuality proofs is the…

Quantum Physics · Physics 2020-01-08 Cihan Okay , Robert Raussendorf

Contextuality is a distinctive feature of quantum theory and a fundamental resource for quantum computation. However, existing examples of contextuality in high-dimensional systems lack the necessary robustness required in experiments. Here…

Bound entanglement, being entangled yet not distillable, is essential to our understandings of the relations between nonlocality and entanglement besides its applications in certain quantum information tasks. Recently, bound entangled…

Quantum Physics · Physics 2017-03-22 Sixia Yu , C. H. Oh

Fully revealing the mathmatical structure of quantum contextuality is a significant task, while some known contextuality theories are only applicable for rank-1 projectors. That is because they adopt the observable-based definitions. This…

Quantum Physics · Physics 2025-01-17 Songyi Liu , Yongjun Wang , Baoshan Wang , Yunyi Jia

An essential ingredient in many examples of the conflict between quantum theory and noncontextual hidden variables (e.g., the proof of the Kochen-Specker theorem and Hardy's proof of Bell's theorem) is a set of atomic propositions about the…

Quantum Physics · Physics 2018-07-11 Adán Cabello , José R. Portillo , Alberto Solís , Karl Svozil

We analyze the validity of Bell and Kochen-Specker theorems under local (or noncontextual) realism but avoiding an assumption of the existence of a joint probability distribution for incompatible observables. We formulate a realist model…

Quantum Physics · Physics 2019-09-13 Ángel Rivas