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A central question in quantum computation is to identify the resources that are responsible for quantum speed-up. Quantum contextuality has been recently shown to be a resource for quantum computation with magic states for odd-prime…

Quantum Physics · Physics 2017-09-26 Juan Bermejo-Vega , Nicolas Delfosse , Dan E. Browne , Cihan Okay , Robert Raussendorf

Quantum mechanics has been subject to logical scrutiny since its inception. The behavior of quantum systems, which are fundamentally dissimilar from classical systems, often appears to point to a logical inconsistency in quantum mechanics,…

Mathematical Physics · Physics 2026-04-01 Felipe Dilho Alves , João Carlos Alves Barata

According to a classical result due to Hudson, the Wigner function of a pure, continuous variable quantum state is non-negative if and only if the state is Gaussian. We have proven an analogous statement for finite-dimensional quantum…

Quantum Physics · Physics 2007-05-23 David Gross

We present a discussion of the extended Wigner's friend thought experiment proposed by Frauchiger and Renner in [1]. We show by using various arguments, including textbook quantum mechanics and the ontological approach of Contexts, Systems,…

Quantum Physics · Physics 2023-01-10 Maxime Federico , Philippe Grangier

Contextuality is a central property in comparative analysis of classical, quantum, and supercorrelated systems. We examine and compare two well-motivated approaches to contextuality. One approach ("contextuality-by-default") is based on the…

Quantum Physics · Physics 2016-01-21 J. Acacio de Barros , Ehtibar N. Dzhafarov , Janne V. Kujala , Gary Oas

States with a negative Wigner function, a significant subclass of nonclassical states, serve as a valuable resource for various quantum information processing tasks. Here, we provide a criterion for detecting such quantum states…

Quantum Physics · Physics 2025-03-06 Bivas Mallick , Sudip Chakrabarty , Saheli Mukherjee , Ananda G. Maity , A. S. Majumdar

We consider in what sense quantum tunnelling is associated with non-classical probabilistic behaviour. We use the Wigner function quasi-probability description of quantum states. We give a definition of tunnelling that allows us to say…

Quantum Physics · Physics 2021-01-04 Yin Long Lin , Oscar C. O. Dahlsten

Contextuality is a fundamental non-classical property of quantum theory, which has recently been proven to be a key resource for achieving quantum speed-ups in some leading models of quantum computation. However, which of the forms of…

Quantum Physics · Physics 2019-04-17 Piers Lillystone , Joel J. Wallman , Joseph Emerson

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

In this work we present a generalization of the recently developed Hardy-like logical proof of contextuality and of the so-called KCBS contextuality inequality for any qudit of dimension greater than three. Our approach uses compatibility…

Quantum Physics · Physics 2016-09-16 Adel Sohbi , Isabelle Zaquine , Eleni Diamanti , Damian Markham

A central problem in quantum information is to determine the minimal physical resources that are required for quantum computational speedup and, in particular, for fault-tolerant quantum computation. We establish a remarkable connection…

Quantum Physics · Physics 2012-11-30 Victor Veitch , Christopher Ferrie , David Gross , Joseph Emerson

We evaluate the gravity-induced negativity volume of the generalized Wigner function in a hybrid system consisting of a particle in a two-localized superposition state and an oscillator. The generalized Wigner function can capture the…

Quantum Physics · Physics 2023-11-21 Daisuke Miki , Akira Matsumura , Kazuhiro Yamamoto

Nonlinear modifications of quantum theory are considered potential candidates for the theory of quantum gravity, with the intuitive argument that since Einstein field equations are nonlinear, quantum gravity should be nonlinear as well.…

Quantum Physics · Physics 2025-06-06 Ruben Campos Delgado , Martin Plávala

Contextuality has been conjectured to be a super-classical resource for quantum computation, analogous to the role of non-locality as a super-classical resource for communication. We show that the presence of contextuality places a lower…

Quantum Physics · Physics 2018-02-23 Angela Karanjai , Joel J. Wallman , Stephen D. Bartlett

The negativity of the discrete Wigner functions (DWFs) is a measure of non-classicality and is often used to quantify the degree of quantum coherence in a system. The study of Wigner negativity and its evolution under different quantum…

Quantum Physics · Physics 2025-09-03 Jai Lalita , K. G. Paulson , Subhashish Banerjee

Contextuality is considered as one of the most distinctive features of nonclassical systems. Here, we show that a Spekkens contextual system (which previous work has shown is a necessary condition for nonclassicality) formed of an…

Quantum Physics · Physics 2026-05-14 Enrico Bozzetto , Jonte R. Hance

Anomalous weak values and Wigner function's negativity are well known witnesses of quantum contextuality. We show that these effects occur when analyzing the energetics of a single qubit gate generated by a resonant coherent field traveling…

The Wigner function plays a central role in QCD as a phase space object encoding correlations among quarks, antiquarks, and gluons, yet its interpretation remains subtle due to its quasiprobabilistic nature and possible negativity. Recent…

High Energy Physics - Phenomenology · Physics 2026-04-07 Chueng-Ryong Ji , Daniel W. Piasecki

It is well known that in quantum mechanics we cannot always define consistently properties that are context independent. Many approaches exist to describe contextual properties, such as Contextuality by Default (CbD), sheaf theory, topos…

Quantum Physics · Physics 2017-07-18 J. Acacio de Barros , Federico Holik , Decio Krause

The quantum backflow effect is a counterintuitive behavior of the probability current of a free particle, which may be negative even for states with vanishing negative momentum component. Here we address the notion of nonclassicality…

Quantum Physics · Physics 2016-09-23 Francesco Albarelli , Tommaso Guaita , Matteo G. A. Paris