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Related papers: A macro-realism inequality for opto-electro-mechan…

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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

The Leggett-Garg inequality holds for any macrorealistic system that is being measured noninvasively. A violation of the inequality can signal that a system does not conform to our primal intuition about the physical world. Alternatively, a…

Quantum Physics · Physics 2017-04-05 Emilie Huffman , Ari Mizel

In contrast to Bell's inequalities which test the correlations between multiple spatially separated systems, the Leggett-Garg inequalities test the temporal correlations between measurements of a single system. We experimentally demonstrate…

Quantum Physics · Physics 2021-11-16 Wenlei Zhang , Ravi K. Saripalli , Jacob M. Leamer , Ryan T. Glasser , Denys I. Bondar

We consider maximal violations of the Leggett-Garg inequality, obtained by maximising over all possible measurement operators, in relation to non-unitary aspects of the system dynamics. We model the action of an environment on a qubit in…

Quantum Physics · Physics 2013-04-22 Clive Emary

Quantum mechanics presents peculiar properties that, on the one hand, have been the subject of several theoretical and experimental studies about its very foundations and, on the other hand, provide tools for developing new technologies,…

The Leggett-Garg (LG) inequalities were introduced to test for the possible presence of macroscopic quantum coherence. Since such effects may be found in various types of macroscopic oscillators, we consider the application of the LG…

Quantum Physics · Physics 2023-12-06 Clement Mawby , Jonathan Halliwell

We realise a quantum three-level system with photons distributed among three different spatial and polarization modes. Ambiguous measurement of the state of the qutrit are realised by blocking one out for the three modes at any one time.…

Quantum Physics · Physics 2018-02-14 Kunkun Wang , Clive Emary , Mengyan Xu , Xiang Zhan , Zhihao Bian , Lei Xiao , Peng Xue

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

The Leggett-Garg inequality, an analogue of Bell's inequality involving correlations of measurements on a system at different times, stands as one of the hallmark tests of quantum mechanics against classical predictions. The phenomenon of…

Quantum Physics · Physics 2016-07-29 J. A. Formaggio , D. I. Kaiser , M. M. Murskyj , T. E. Weiss

The Leggett-Garg (LG) inequalities were proposed in order to assess whether sets of pairs of sequential measurements on a single quantum system can be consistent with an underlying notion of macrorealism. Here, the LG inequalities are…

Quantum Physics · Physics 2016-03-02 J. J. Halliwell

Macroscopic realism (MR) is the notion that a time-evolving system possesses definite properties, irrespective of past or future measurements. Quantum mechanical theories can, however, produce violations of MR. Most research to date has…

Quantum Physics · Physics 2021-09-14 Shayan Majidy , Jonathan J. Halliwell , Raymond Laflamme

We investigate the Leggett-Garg inequalities (LGIs) for a boson system whose observables are given by deforming the Pegg-Barnett phase operators. We consider two observables and show that the quantum Fourier transform is useful in the…

Quantum Physics · Physics 2023-02-09 Hiroo Azuma , William J. Munro , Kae Nemoto

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

The Leggett-Garg inequalities serve to test whether or not quantum correlations in time can be explained within a classical macrorealistic framework. We apply this test to thermodynamics and derive a set of Leggett- Garg inequalities for…

Quantum Physics · Physics 2018-04-10 Harry J. D. Miller , Janet Anders

In this study, we determine a violation of the Leggett-Garg inequalities due to gravitational interaction in a hybrid system consisting of a harmonic oscillator and a spatially localized superposed particle. The violation of the…

Quantum Physics · Physics 2022-08-23 Akira Matsumura , Yasusada Nambu , Kazuhiro Yamamoto

Despite the great success of quantum mechanics, questions regarding its application still exist and the boundary between quantum and classical mechanics remains unclear. Based on the philosophical assumptions of macrorealism and noninvasive…

Quantum Physics · Physics 2012-04-24 Jin-Shi Xu , Chuan-Feng Li , Xu-Bo Zou , Guang-Can Guo

We investigate the violation of the Leggett-Garg inequalities for a quantum field, focusing on the two-time quasi-probability distribution function of the dichotomic variable with a coarse-grained scalar field. The Leggett-Garg inequalities…

Quantum Physics · Physics 2023-11-07 Masaki Tani , Kosei Hatakeyama , Daisuke Miki , Yuki Yamasaki , Kazuhiro Yamamoto

The rise of quantum information theory has lent new relevance to experimental tests for non-classicality, particularly in controversial cases such as adiabatic quantum computing superconducting circuits. The Leggett-Garg inequality is a…

Quantum Physics · Physics 2015-03-13 Mark M. Wilde , Ari Mizel

For multilevel spin systems, robustness of the quantum mechanical (QM) violation of macrorealism (MR) with respect to coarse grained measurements is investigated using three different necessary conditions of MR, namely, the Leggett-Garg…

Quantum Physics · Physics 2016-12-28 Shiladitya Mal , Debarshi Das , Dipankar Home

Macro-realism is the position that certain "macroscopic" observables must always possess definite values: e.g. the table is in some definite position, even if we don't know what that is precisely. The traditional understanding is that by…

Quantum Physics · Physics 2017-07-17 John-Mark A. Allen , Owen J. E. Maroney , Stefano Gogioso