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Related papers: Leggett-Garg inequalities for multitime processes

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The Leggett-Garg inequality (LGI) serves as a criterion to determine the adherence of macroscopic system dynamics to macrorealism, as introduced by Leggett and Garg. A violation of this inequality implies either the absence of a realistic…

Quantum Physics · Physics 2025-02-24 Tsubasa Sakamoto , Ryosuke Yoshii , Shunji Tsuchiya

We present a phase space formalism to evaluate Bell inequality violations in continuous variable systems. By doing so we can generalize previous analyses (which have dealt only with pure states) to arbitrary mixed states. We leverage these…

Quantum Physics · Physics 2025-01-09 Gurpahul Singh , Kelly Wurtz , Eduardo Martín-Martínez

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…

In the cryptographic context, an earlier unexplored application of the temporal version of the Bell-type inequality is shown here in the device-independent (DI) scenario. This is done by using the Leggett-Garg inequality (LGI) to…

Quantum Physics · Physics 2016-02-25 Akshata Shenoy H. , S. Aravinda , R. Srikanth , D. Home

The possibility of observing violations of temporal Bell inequalities, originally proposed by Leggett as a mean of testing the quantum mechanical delocalization of suitably chosen macroscopic bodies, is discussed by taking into account the…

Quantum Physics · Physics 2009-10-31 Tommaso Calarco , Marcello Cini , Roberto Onofrio

The Leggett-Garg inequalities probe the classical-quantum boundary by putting limits on the sum of pairwise correlation functions between classical measurement devices that consecutively measured the same quantum system. The apparent…

Quantum Physics · Physics 2019-09-13 Christoph Adami

In 1985, Leggett and Garg formulated a class of inequalities for testing the compatibility between macrorealism and quantum mechanics. In this paper, we point out that based on the same assumptions of macrorealism that are used in the…

Quantum Physics · Physics 2020-12-29 A. K. Pan , Md. Qutubuddin , Swati Kumari

We introduce two entanglement conditions that take the form of inequalities involving expectation values of operators. These conditions are sufficient conditions for entanglement, that is if they are satisfied the state is entangled, but if…

Quantum Physics · Physics 2015-05-19 Mark Hillery , Ho Trung Dung , Hongjun Zheng

According to the world view of macrorealism, the properties of a given system exist prior to and independent of measurement, which is incompatible with quantum mechanics. Leggett and Garg put forward a practical criterion capable of…

Quantum Physics · Physics 2018-06-27 Eugenio Roldán , Johannes Kofler , Carlos Navarrete-Benlloch

Leggett-Garg Inequality~(LGI) is a time analogue of Bell's inequality that concerns measurements performed on a system at different times. Violation to LGI indicates quantum coherence. We present a Leggett-Garg-type inequality compatible…

Quantum Physics · Physics 2022-02-15 Xing-Zhi Wang , Bo-Qiang Ma

We consider tests of Leggett-Garg's macrorealism and of macroscopic local realism, where for spacelike separated measurements the assumption of macroscopic noninvasive measurability is justified by that of macroscopic locality. We give a…

Quantum Physics · Physics 2024-12-03 Manushan Thenabadu , M. D. Reid

We propose a test of macrorealism that exploits the contextuality of two-time correlation functions to escape the so-called "clumsiness loophole" that plagues Leggett-Garg inequalities. The non-contextuality of reduced joint probability…

Quantum Physics · Physics 2023-11-15 Devashish Pandey , Xavier Oriols , Guillermo Albareda

Macro-realistic description of systems is based majorly on two basic intuitions about the classical world, namely, macrorealism per se, that is, the system is always in a distinct state, and non-invasive measurements, that is, measurements…

Quantum Physics · Physics 2025-06-16 Shubhayan Sarkar

We investigate violations of Leggett-Garg inequalities (LGIs) for a harmonic oscillator and a (1+1)-dimensional chiral scalar field with coherent-state projectors, which is equivalent to a heterodyne-type measurement scheme. For the…

Quantum Physics · Physics 2024-01-30 Tomoya Hirotani , Akira Matsumura , Yasusada Nambu , Kazuhiro Yamamoto

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

This paper analyzes Sch\"odinger operators from viewpoint of correlation inequalities. We construct Griffiths inequalities for the ground state expectations by applying operator-theoretic correlation inequalities. As an example of such an…

Mathematical Physics · Physics 2019-11-25 Tadahiro Miyao

We discuss experimental situations that consist of multiple preparation and measurement stages. This leads us to a new approach to quantum mechanics. In particular, we introduce the idea of multi-time quantum states which are the…

Quantum Physics · Physics 2013-05-29 Y. Aharonov , S. Popescu , J. Tollaksen , L. Vaidman

The Leggett-Garg inequality (LGI) is a powerful tool for distinguishing between quantum and classical properties in studies of macroscopic systems. Applying the LGI to non-Hermitian systems with dissipation presents a fascinating…

Quantum Gases · Physics 2024-11-06 Qinxuan Peng , Bolong Jiao , Hang Yu , Liao Sun , Haoyi Zhang , Jiaming Li , Le Luo

This paper is interested in proving correlation inequalities of the FKG-type for various stochastic processes in continuous time. The pivotal tool which yields these correlation inequalities is an approximation with (possibly conditioned)…

Probability · Mathematics 2025-07-14 Alexandre Legrand

We consider two necessary and sufficient conditions for macrorealism recently appeared in the literature, known as no-signaling-in-time and arrow-of-time conditions, respectively, and study them in the context of neutrino flavor…

High Energy Physics - Theory · Physics 2023-08-07 Massimo Blasone , Fabrizio Illuminati , Luciano Petruzziello , Kyrylo Simonov , Luca Smaldone