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We propose a new Wigner inequality suitable for test of the hypothesis of realism. We show that this inequality is not identical neither to the well-known Wigner inequality nor to the Leggett-Garg inequality in Wigner form. The obtained…

Quantum Physics · Physics 2019-12-18 N. Nikitin , K. Toms

Macroscopic Realism (MR) says that a macroscopic system is always determinately in one or other of the macroscopically distinguishable states available to it. The Leggett-Garg (LG) inequality was derived to allow experimental test of…

Quantum Physics · Physics 2014-12-22 Owen J. E Maroney , Christopher G Timpson

In an endeavour to better define the distinction between classical macroscopic and quantum microscopic regimes, the Leggett-Garg inequalities were established as a test of macroscopic-realistic theories, which are commonly thought to be a…

Quantum Physics · Physics 2021-04-14 Hadrien Chevalier , A. J. Paige , Hyukjoon Kwon , M. S. Kim

We prove that a violation of a Leggett-Garg inequality for bounded observables in stationary pure states and thermal states yields a rigorous lower bound on the quantum Fisher information. This turns a qualitative foundations test of…

Quantum Physics · Physics 2026-04-14 Nick Abboud , Yuntao Guan , Barry Bradlyn , Jorge Noronha

We construct quantifiable generalisations of Leggett-Garg tests for macro/ mesoscopic realism and noninvasive measurability that apply when not all outcomes of measurement can be identified as arising from one of two macroscopically…

Quantum Physics · Physics 2024-12-13 L. Rosales-Zárate , B. Opanchuk , Q. Y. He , M. D. Reid

I study several aspects of tests of macrorealism (MR), which for a given data set serves to give a quantitative signal of the presence of a specific notion of non-classical behaviour. The insufficiency of classical understanding underpins…

Quantum Physics · Physics 2024-02-27 Clement Mawby

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

We investigate Leggett-Garg temporal inequalities in flavor-mixing processes. We derive an exact flavor-mass uncertainty product and we establish that it is an upper bound to the violation of the inequalities. This finding relates temporal…

Quantum Physics · Physics 2021-12-10 Massimo Blasone , Fabrizio Illuminati , Luciano Petruzziello , Luca Smaldone

A kicked quantum nondemolition measurement is introduced, where a qubit is weakly measured by pumping current. Measurement statistics are derived for weak measurements combined with single qubit unitary operations. These results are applied…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Andrew N. Jordan , Alexander N. Korotkov , Markus Buttiker

Temporal steering and violation of the Leggett-Garg inequality are two different ways of probing the violation of macro-realistic assumptions in quantum mechanics. It is shown here that under unitary evolution and projective measurements…

Quantum Physics · Physics 2016-11-18 Shiladitya Mal , Archan S. Majumdar , Dipankar Home

An operational (measurement based) scheme that connects measurement invasiveness and the presence of non-classical memory effects in open quantum systems is defined. Its underlying theoretical basis relies on a non-invasive measurability of…

Quantum Physics · Physics 2025-07-09 Adrián A. Budini

Macroscopic realism is a set of assumptions about how we experience the world at a classical level. While the Leggett-Garg inequalities are temporal correlations that are violated by quantum systems not obeying such macrorealism, the…

Quantum Physics · Physics 2025-12-23 Manish Ramchander , Arul Lakshminarayan

We propose an experimental programme to test Leggett--Garg-type temporal correlations in single-neuron dynamics. The goal is to distinguish between diffusive (Wiener/cable-equation) models and non-diffusive persistent stochastic models…

Quantum Physics · Physics 2026-05-13 Partha Ghose

Leggett-Garg inequalities place bounds on the temporal correlations of a system based on the principles of macroscopic realism $\textit{per se}$ and noninvasive measurability. Their conventional formulation relies on the ensemble-averaged…

Quantum Physics · Physics 2024-06-27 Masahiro Hotta , Sebastian Murk

Hybrid quantum-classical systems constitute a promising architecture for useful control strategies of quantum systems by means of a classical device. Here we provide a comprehensive study of the dynamics of various manifestations of…

Quantum Physics · Physics 2020-01-27 Hossein Gholipour , Ali Mortezapour , Farzam Nosrati , Rosario Lo Franco

We discuss a scheme for macrorealistic theories of the Leggett-Garg form [A. J. Leggett and A. Garg, Phys. Rev. Lett. 54, 857 (1985)]. Our scheme is based on a hybrid optomechanical system. It seems reasonable to test these inequalities…

Quantum Physics · Physics 2020-03-13 Marta Maria Marchese , Hannah McAleese , Angelo Bassi , Mauro Paternostro

We study some aspects of the Leggett-Garg inequalities by using the operator-state formalism for multitime processes. The process tensor in its Choi-state form, which we call process state, is employed to investigate the Leggett-Garg…

Quantum Physics · Physics 2025-06-12 Zhiqiang Huang , Xiao-Kan Guo

Macro-realism is a fundamental feature of classical world that contradicts with the quantum theory. An elegant method of testing macrorealism is to apply the Leggett-Garg inequality (LGI), but the non-invasivity of measurement is…

Quantum Physics · Physics 2023-02-20 Hui Wang , Shuang Wang , Cong-Feng Qiao

A quantum decaying system can reveal its nonclassical behavior by being noninvasively measured. Correlations of weak measurements in the noninvasive limit violate the classical bound for a universal class of systems. The violation is…

Quantum Physics · Physics 2022-04-20 Stanisław Sołtan , Adam Bednorz

We investigate the Leggett-Garg inequalities and the relative entropy of coherence in the Bixon-Jortner model. First, we analytically derive the general solution of the Bixon-Jortner model by a technique of the Laplace transform. So far,…

Quantum Physics · Physics 2018-10-30 Hiroo Azuma , Masashi Ban