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The behavior of total purely quantum correlation (discord) in dimers consisting of dipolar-coupled spins 1/2 is studied. We found that the discord Q=0 at the absolute zero temperature. With increasing the temperature $T$, at first the…

Quantum Physics · Physics 2013-01-24 E. I. Kuznetsova , M. A. Yurishchev

Long-range quantum correlations between particles are usually formulated by assuming the persistence of an entangled state after the particles have spearated. Here this approach is re-examined based upon studying the correlations present in…

Quantum Physics · Physics 2025-04-03 B. C. Sanctuary

Recent results in quantum information theory characterize quantum coherence in the context of resource theories. Here we study the relation between quantum coherence and quantum discord, a kind of quantum correlation which appears even in…

Quantum Physics · Physics 2016-04-29 Jiajun Ma , Benjamin Yadin , Davide Girolami , Vlatko Vedral , Mile Gu

We study nonclassical correlations in propagating two-mode squeezed microwave states in the presence of noise. We focus on two different types of correlations, namely, quantum entanglement and quantum discord. Quantum discord has various…

We analyze the effects of quantum correlations, such as entanglement and discord, on the efficiency of phase estimation by studying four quantum circuits that can be readily implemented using NMR techniques. These circuits define a standard…

Quantum Physics · Physics 2012-01-04 Kavan Modi , Hugo Cable , Mark Williamson , Vlatko Vedral

Quantum entanglement has long been recognized as an important resource for quantum sensing. In this work, we demonstrate the use of multiple-quantum solid-state NMR for quantum sensing by creating, manipulating, and detecting large clusters…

Quantum Physics · Physics 2025-12-02 Conan Alexander , T S Mahesh

A new family of supramolecular, antiferromagnetically exchange-coupled dimers of single-molecule magnets (SMMs) has recently been reported [W. Wernsdorfer, N. Aliaga-Alcalde, D.N. Hendrickson, and G. Christou, Nature 416, 406 (2002)]. Each…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Tiron , W. Wernsdorfer , D. Foguet-Albiol , N. Aliaga-Alcalde , G. Christou

We study the quantum correlations in a 2D system that possesses a topological quantum phase transition. The quantumness of two-body correlations is measured by quantum discord. We calculate both the correlation of two local spins and that…

Quantum Physics · Physics 2015-05-14 Yi-Xin Chen , Sheng-Wen Li

We show that a von Neumann measurement on a part of a composite quantum system unavoidably creates distillable entanglement between the measurement apparatus and the system if the state has nonzero quantum discord. The minimal distillable…

Quantum Physics · Physics 2011-05-03 Alexander Streltsov , Hermann Kampermann , Dagmar Bruß

Quantum Discord (QD) is a measure of the total quantum non-local correlations of a quantum system. The formalism of quantum discord has been applied to various two-qubit mixed states and it has been reported that there is a non-zero quantum…

Quantum Physics · Physics 2022-10-04 M. S. Ramkarthik , Devvrat Tiwari , Pranay Barkataki

In this letter we study thermal quantum correlations as quantum discord and entanglement in bipartite system imposed by external magnetic field with Herring-Flicker coupling ie. $J(R)=1.642 e^{-2 R} R^{5/2}+O(R^{2}e^{-2R})$. The…

Quantum Physics · Physics 2018-01-16 Kapil K. Sharma

Quantum entanglement manifests as a distinctive correlation between particles that transcends classical boundaries when their quantum states cannot be described independently. On the other hand, as quantum systems interact with their…

Quantum Physics · Physics 2025-08-21 Samuel Marquez Gonzalez

The development and improvement of analytical methods for evaluating nonclassical correlations is one of the most important tasks in quantum information science. In this paper, we investigate a mixed spin-$(1/2,S)$ system with an arbitrary…

Quantum Physics · Physics 2025-06-06 Saeed Haddadi , Elena I. Kuznetsova , M. A. Yurischev

Quantum coherence as an important quantum resource plays a key role in quantum theory. In this paper, using entropy-based measures, we investigate the relations between quantum correlated coherence, which is the coherence between subsystems…

Quantum Physics · Physics 2017-03-03 Xiao-Li Wang , Qiu-Ling Yue , Chao-Hua Yu , Fei Gao , Su-Juan Qin

Although quantum correlations in a quantum system are characterized by the evolving quantities (which are entanglement and discord usually), we reveal such basis (i.e. the set of virtual particles) for the representation of the density…

Quantum Physics · Physics 2015-02-11 E. B. Fel'dman , A. I. Zenchuk

Quantum-classical transitions have long attracted much attention. We study such transitions in quantum spin-($j$,1/2) systems at thermal equilibrium. Unlike the previous work [Phys. Rev. A 73, 064302 (2006)], it is found that the threshold…

Quantum Physics · Physics 2025-10-15 M. A. Yurischev , E. I. Kuznetsova , Saeed Haddadi

Quantum metrology exploits quantum mechanical laws to improve the precision in estimating technologically relevant parameters such as phase, frequency, or magnetic fields. Probe states are usually tailored on the particular dynamics whose…

The fundamental quantum dynamics of two interacting oscillator systems are studied in two different scenarios. In one case, both oscillators are assumed to be linear, whereas in the second case, one oscillator is linear and the other is a…

Quantum Physics · Physics 2015-06-26 ILki Kim , Gerald J. Iafrate

An isolated spin system that is in internal thermodynamic equilibrium and that has an upper limit to its allowed energy states can possess a negative temperature. We calculate the thermodynamic characteristics and the concurrence in this…

Quantum Physics · Physics 2015-06-15 G. B. Furman , V. M. Meerovich , V. L. Sokolovsky

The ground state of a quantum spin chain is a natural playground for investigating correlations. Nevertheless, not all correlations are genuinely of quantum nature. Here we review the recent progress to quantify the 'quantumness' of the…

Quantum Physics · Physics 2015-03-20 Marcelo S. Sarandy , Thiago R. de Oliveira , Luigi Amico