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In contrast to the spatial Bell's inequalities, which probe entanglement between spatially-separated systems, the Leggett-Garg inequalities test the correlations of a single system measured at different times. Violation of a genuine…

Quantum Physics · Physics 2014-01-31 Clive Emary , Neill Lambert , Franco Nori

We generalize the derivation of Leggett-Garg inequalities to systematically treat a larger class of experimental situations by allowing multi-particle correlations, invasive detection, and ambiguous detector results. Furthermore, we show…

Quantum Physics · Physics 2015-03-18 J. Dressel , C. J. Broadbent , J. C. Howell , A. N. Jordan

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…

A quantum memory or information processing device is subject to disturbance from its surrounding environment or inevitable leakage due to its contact with other systems. To tackle these problems, several control protocols have been proposed…

Quantum Physics · Physics 2016-10-21 Jun Jing , Lian-Ao Wu

The Leggett-Garg inequality (LGI), based on the notions of realism and noninvasive measurability, is applied in the context of a linear harmonic oscillator. It is found that merely through observing at various instants which region of the…

Quantum Physics · Physics 2015-09-02 S. Bose , D. Home , S. Mal

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 study the symmetry properties in the dynamics of quantum correlations for two-qubit systems in one-sided noisy channels, with respect to a switch in the location of noise from one qubit to the other. We consider four different channel…

Quantum Physics · Physics 2017-08-25 Henri Lyyra , Göktuğ Karpat , Chuan-Feng Li , Guang-Can Guo , Jyrki Piilo , Sabrina Maniscalco

We provide necessary and sufficient conditions for freezing of quantum correlations as measured by quantum discord and quantum work deficit in the case of bipartite as well as multipartite states subjected to local noisy channels. We…

Quantum Physics · Physics 2015-09-11 Titas Chanda , Amit Kumar Pal , Anindya Biswas , Aditi Sen De , Ujjwal Sen

The high-fidelity storage of quantum information is crucial for quantum computation and communication. Many experimental platforms for these applications exhibit highly biased noise, with good resilience to spin depolarisation undermined by…

Quantum Physics · Physics 2023-05-31 Yannick Seis , Benjamin J. Brown , Anders S. Sørensen , Joseph F. Goodwin

In this research, we analyze two models using the tensor network algorithm. The quantum correlations of a two-qubit system are first studied in different bosonic reservoirs. Both equilibrium and nonequilibrium scenarios are discussed.…

Quantum Physics · Physics 2022-11-23 He Wang , Liufang Xu , Jin Wang

We analyze the effect of decoherence, modelled by local quantum channels, on quantum critical states and we find universal properties of the resulting mixed state's entanglement, both between system and environment and within the system.…

Quantum Physics · Physics 2023-07-05 Yijian Zou , Shengqi Sang , Timothy H. Hsieh

Recently it has been demonstrated by Albo that partial coherence analysis is sensitive to signal to noise ratio (SNR) and that it will always identify the signal with the highest SNR among the three signals as the main (driving) influence.…

Medical Physics · Physics 2007-05-23 R. B. Govindan , J. Raethjen , K. Arning , F. Kopper , G. Deuschl

We study the nonlocal properties of two-qubit maximally-entangled and N-qubit Greenberger-Horne-Zeilinger states under local decoherence. We show that the (non)resilience of entanglement under local depolarization or dephasing is not…

Quantum Physics · Physics 2015-06-04 Rafael Chaves , Daniel Cavalcanti , Leandro Aolita , Antonio Acín

We show that vacuum induced coherence in three level atomic systems can lead to preservation of bi-partite entanglement, when two such atoms are prepared as two initially entangled qubits each independently interacting with their respective…

Quantum Physics · Physics 2015-05-18 Sumanta Das , G. S. Agarwal

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

We examine the emergence of dynamical memory effects in quantum processes having indefinite time direction and causal order. In particular, we focus on the class of phase-covariant qubit channels, which encompasses some of the most…

Quantum Physics · Physics 2024-07-23 Göktuğ Karpat , Barış Çakmak

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

Local available quantum correlations (LAQCs), as defined by Mundarain et al. [19], are analytically determined for Bell Diagonal states. Using the Kraus operators formalism [10], we analyze the dissipative dynamics of 2-qubit LAQCs under…

Quantum Physics · Physics 2018-11-06 Hermann Albrecht , Douglas Mundarain , Mario Caicedo

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

Demonstrating contextual correlations in quantum theory through the violation of a non-contextuality inequality necessarily needs some ``contexts" and thus assumes some compatibility relations between the measurements. As a result, any…

Quantum Physics · Physics 2024-12-03 Gautam Sharma , Chellasamy Jebarathinam , Sk Sazim , Remigiusz Augusiak