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Related papers: Leggett-Garg inequalities for multitime processes

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In the present paper we introduce a way of identifying quantum phase transitions of many-body systems by means of local time correlations and Leggett-Garg inequalities. This procedure allows to experimentally determine the quantum critical…

Quantum Physics · Physics 2016-01-25 F. J. Gómez-Ruiz , J. J. Mendoza-Arenas , F. J. Rodríguez , C. Tejedor , L. Quiroga

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

In two-party, two-input and two-output measurement scenario only relevant Bell's inequality is the Clauser-Horne-Shimony-Holt (CHSH) form. They also provide the necessary and sufficient conditions for local realism. Any other form, such as,…

Quantum Physics · Physics 2019-12-24 Swati Kumari , A. K. Pan

Nonclassicality of temporal correlations pertaining to noncommutative sequential measurements is defined through the violation of macrorealistic inequalities, known as Leggett-Garg inequalities (LGI). We investigate the energy cost of the…

Quantum Physics · Physics 2018-09-11 Titas Chanda , Tamoghna Das , Shiladitya Mal , Aditi Sen De , Ujjwal Sen

We show that the quantum bound for temporal correlations in a Leggett-Garg test, analogous to the Tsirelson bound for spatial correlations in a Bell test, strongly depends on the number of levels $N$ that can be accessed by the measurement…

Quantum Physics · Physics 2014-07-31 Costantino Budroni , Clive Emary

It remains an open question how realist view of macroscopic world emerges from quantum formalism. For testing the macrorealism in quantum domain, an interesting approach was put forward by Leggett and Garg in $1985$, by formulating a…

Quantum Physics · Physics 2017-08-16 Swati Kumari , A. K. Pan

Macrorealism formalizes the intuitive notion that at any given time the system occupies a definite state and that the evolution of the system is independent of the measurements performed on it, in contrast to the principles of quantum…

We interpret the Leggett-Garg (LG) inequality as a kind of contextual probabilistic inequality in which one combines data collected in experiments performed for three different contexts. In the original version of the inequality these…

Neurons and Cognition · Quantitative Biology 2015-06-18 Masanari Asano , Takahisa Hashimoto , Andrei Khrennikov , Masanori Ohya , Yoshiharu Tanaka

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

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

Ambiguous measurements do not reveal complete information about the system under test. Their quantum-mechanical counterparts are semi-weak (or in the limit, weak-) measurements and here we discuss their role in tests of the Leggett-Garg…

Quantum Physics · Physics 2017-10-11 Clive Emary

The Leggett and Garg Inequality (LGI) is a test of the classical behaviour of an observed system, in the case of a single measurement channel monitored at different times. Here we report LGI violation in cognitive tasks consisting in the…

Neurons and Cognition · Quantitative Biology 2013-05-27 F. T. Arecchi , A. Farini , N. Megna

This study investigates the emergence of macroscopic classical behavior from quantum foundations via the entropic Leggett--Garg inequality. We introduce a geometric framework for deriving entropic Leggett--Garg inequalities with…

Quantum Physics · Physics 2025-12-01 Qi-Hong Cai , Xue-Hao Yu , Ma-Cheng Yang , Ao-Xiang Liu , Cong-Feng Qiao

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

We investigate the three-term Leggett-Garg inequality (LGI) for a two-level quantum system undergoing parity-time (PT ) symmetric dynamics governed by a non-Hermitian Hamiltonian, when a sequence of dichotomic projective measurements are…

Quantum Physics · Physics 2021-03-24 H. S. Karthik , Akshata Shenoy Hejamadi , A. R. Usha Devi

"Macrorealism" posits that a system possesses definite properties at all times and that we can discover these properties, in principle, without disturbing the system's subsequent behaviour. The Leggett-Garg inequalities are derived under…

Quantum Physics · Physics 2026-05-22 Arush Garg , Jonathan Halliwell , Taejas Venkataraman

The Leggett-Garg inequalities have been proposed to identify the quantum behaviour of a system; specifically, the violation of macrorealism. They are usually implemented by performing two sequential measurements on quantum systems,…

Quantum Physics · Physics 2025-02-25 D. Melegari , M. Cardi , P. Solinas

Leggett-Garg inequality (LGI) studies the temporal correlation in the evolution of physical systems. Classical systems obey the LGI but quantum systems may violate it. The extent of the violation depends on the dimension of the quantum…

Quantum mechanics violates Leggett-Garg inequalities because the operator formalism predicts correlations between different spin components that would correspond to negative joint probabilities for the outcomes of joint measurements.…

Quantum Physics · Physics 2015-03-20 Yutaro Suzuki , Masataka Iinuma , Holger F. Hofmann

We discuss the use of inequalities of the Leggett-Garg type (LGtI) to witness quantum coherence and present the first experimental violation of this type of inequalities using a light-matter interfaced system. By separately benchmarking the…

Quantum Physics · Physics 2015-09-11 Zong-Quan Zhou , Susana F. Huelga , Chuan-Feng Li , Guang-Can Guo