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An implementation of weak values is investigated in solid-state qubits. We demonstrate that a weak value can be non-classical if and only if a Leggett-Garg inequality can also be violated. Generalized weak values are described, where…

Mesoscale and Nanoscale Physics · Physics 2008-01-16 Nathan S. Williams , Andrew N. Jordan

Efforts to construct deeper, realistic, level of physical description, in which individual systems have, like in classical physics, preexisting properties revealed by measurements are known as hidden-variable programs. Demonstrations that a…

Quantum Physics · Physics 2009-09-15 Caslav Brukner , Marek Zukowski

We argue that the intractable part of the measurement problem -- the 'big' measurement problem -- is a pseudo-problem that depends for its legitimacy on the acceptance of two dogmas. The first dogma is John Bell's assertion that measurement…

Quantum Physics · Physics 2008-05-19 Jeffrey Bub , Itamar Pitowsky

It is widely accepted that the violation of Bell inequalities excludes local theories of the quantum realm. This paper presents a new derivation of the inequalities from non-trivial non-local theories and formulates a stronger Bell argument…

Quantum Physics · Physics 2018-07-06 Paul M. Näger

We consider temporal correlations of particles with arbitrary spin. We show that the Leggett-Garg inequality can be maximally violated irrespective of the value of spin, thus improving upon an earlier result by Kofler and Brukner [Phys.…

Quantum Physics · Physics 2016-06-22 Shiladitya Mal , A. S Majumdar

Recently, table-top experiments involving massive quantum systems have been proposed to test the interface of quantum theory and gravity. In particular, the crucial point of the debate is whether it is possible to conclude anything on the…

Quantum Physics · Physics 2023-02-23 Thomas D. Galley , Flaminia Giacomini , John H. Selby

The Leggett-Garg inequality (LGI) as a temporal analogue of Bell's inequality, derived using the notion of realism, is applied in a hitherto unexplored context involving the weak interaction induced two-state oscillations of decaying…

Quantum Physics · Physics 2015-06-15 D. Gangopadhyay , D. Home , A. Sinha Roy

In this, partly pedagogical review, I attempt to give a self-contained overview of the basis of (non-relativistic) QM measurement theory expressed in density matrix formalism. The focus is on applications to the theory of weak measurement,…

Quantum Physics · Physics 2013-05-27 Bengt E. Y. Svensson

Two typical entanglements will be shown to stand on opposite sides on the issue of \emph{instrumental realism}, the issue of whether (as for EPR in the original form or EPRB, Bohm's versions using spin) or not (as for GHZ) observables have…

Quantum Physics · Physics 2007-05-23 Charles Tresser

Classical realism demands that system properties exist independently of whether they are measured, while noncontextuality demands that the results of measurements do not depend on what other measurements are performed in conjunction with…

Despite several approaches proposed to operationally characterize quantum states of light-those that cannot be sampled with a positive distribution over classical states-most existing formulations suffer from limited practicality or rely on…

Quantum Physics · Physics 2025-12-01 Soumyakanti Bose , Yong-Siah Teo , Hyukjoon Kwon , Hyunseok Jeong

Quantum theory is applicable, in principle, to both the microscopic and macroscopic realms. It is therefore worthwhile to investigate whether it is possible to evolve a quantum-compatible view of the properties and states of macroscopic…

Quantum Physics · Physics 2007-08-14 Ravi Gomatam

We formulate a spatial extension of the Leggett-Garg inequality by considering three distant observers locally measuring a many-body system at three subsequent times. The spatial form, in particular, is specially suited to analyze…

Quantum Physics · Physics 2025-07-08 Guillem Müller-Rigat , Donato Farina , Maciej Lewenstein , Andrea Tononi

This short note addresses the criticisms recently proposed by Shan Gao against our article "On the Reality of the Quantum State Once Again: A No-Go Theorem for {\psi}-Ontic Models" (Found. Phys. 54:14). The essay aims to respond to such…

Quantum Physics · Physics 2024-12-30 Gabriele Carcassi , Andrea Oldofredi , Christine A. Aidala

Contextuality means non-existence of a joint distribution for random variables recorded under mutually incompatible conditions, subject to certain constraints imposed on how the identity of these variables may change across these…

Quantum Physics · Physics 2015-02-06 Ehtibar N. Dzhafarov , Janne V. Kujala

Relational quantum mechanics (RQM) proposes an ontology of relations between physical systems, where any system can serve as an `observer' and any physical interaction between systems counts as a `measurement'. Quantities take unique values…

Quantum Physics · Physics 2021-12-30 Jacques L. Pienaar

The Leggett-Garg inequality (LGI) distinguishes nonmacrorealistic channels from macrorealistic ones by constraining the experimental outcomes of the underlying system. In this work, we propose a class of channels which, initially, cannot…

We investigate the intrinsic ambiguity in the definition of correlation functions arising from the inevitable invasiveness of quantum measurements. While algebraic correlations defined as expectation values of products of observables are…

Quantum Physics · Physics 2026-03-05 Shun Umekawa , Jaeha Lee

Our notions of what is physically 'real' have long been based on the idea that the real is what is immediately apprehended, that is the local or observable, the physically tangible, though there has always been an alternative philosophical…

General Physics · Physics 2009-12-18 Peter Rowlands

Although coherent manipulation of electronic states can be achieved in quantum dot (QD) devices by harnessing nanofabrication tools, it is often hard to fathom the extent to which these nanoelectronic devices can behave quantum…

Quantum Physics · Physics 2024-10-25 Thingujam Yaiphalemba Meitei , Saikumar Krithivasan , Arijit Sen , Md Manirul Ali