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Entanglement is known to be an essential resource for many quantum information processes. However, it is now known that some quantum features may be acheived with quantum discord, a generalized measure of quantum correlation. In this paper,…

In an initially uncorrelated mixed separable bi-partite system, quantum correlations can emerge under the action of a local measurement or local noise [A. Streltsov, H. Kampermann, and D. Bru\ss{}, Phys. Rev. Lett. 107, 170502 (2011)]. We…

Quantum Physics · Physics 2015-06-17 Richard Tatham , Natalia Korolkova

The frame of classical probability theory can be generalized by enlarging the usual family of random variables in order to encompass nondeterministic ones: this leads to a frame in which two kinds of correlations emerge: the classical…

Quantum Physics · Physics 2007-05-23 E. G. Beltrametti , S. Bugajski

Recently some authors have pointed out that there exist nonclassical correlations which are more general, and possibly more fundamental, than entanglement. For these general quantum correlations and their classical counterparts, under the…

Quantum Physics · Physics 2009-10-08 J. Maziero , L. C. Celeri , R. M. Serra , V. Vedral

Grover search is a well-known quantum algorithm that outperforms any classical search algorithm. It is known that quantum correlations such as entanglement are necessary for the power of quantum computation. But entanglement is not the only…

Quantum Physics · Physics 2010-01-05 Jian Cui , Heng Fan

In this work we developed a general approach to the problem of detecting and quantifying different kind of correlations in bipartite quantum systems. Our method is based on the use of distances between quantum states and processes. We rely…

Quantum Physics · Physics 2019-02-27 D. G. Bussandri , A. P. Majtey , P. W. Lamberti , T. M. Osán

Originally introduced as the difference between two possible forms of quantum mutual information, quantum discord has posteriorly been shown to admit a formulation according to which it measures a distance between the state under scrutiny…

Quantum Physics · Physics 2018-10-01 P. R. Dieguez , R. M. Angelo

Quantum correlations of 3-beam symmetric Gaussian states are analyzed using their quantum universal invariants. These invariants, 1-, 2-, and 3-beam purities, are expressed in terms of the beams' intensity moments up to sixth order. The…

Quantum Physics · Physics 2025-11-26 Jan Peřina , Nazarii Sudak , Artur Barasiński , Antonín Černoch

We address the dynamics of entanglement and quantum discord for two non interacting qubits initially prepared in a maximally entangled state and then subjected to a classical colored noise, i.e. coupled with an external environment…

Quantum Physics · Physics 2013-06-06 C. Benedetti , F. Buscemi , P. Bordone , M. G. A. Paris

Weak measurement is a new way to manipulate and control quantum systems. Different from projection measurement, weak measurement only makes a small change in status. Applying weak measurement to quantum discord, Singh and Pati proposed a…

Quantum Physics · Physics 2015-02-16 Tao Li , Teng Ma , Yaokun Wang , Shaoming Fei , Zhixi Wang

We introduce a framework to identify where the total correlations and entanglement with a chosen degree of freedom reside within the rest of a system, in the context of bosonic many-body Gaussian quantum systems. Our results are organized…

In this Letter we exploit the recently-solved conjecture on the bosonic minimum output entropy to show the optimality of Gaussian discord, so that the computation of quantum discord for bipartite Gaussian states can be restricted to local…

Measuring the quantumness of a system can be done with a variety of methods. In this article we compare different criteria, namely quantum discord, Bell inequality violation and non-separability, for systems placed in a Gaussian state. When…

Quantum Physics · Physics 2023-04-19 Jerome Martin , Amaury Micheli , Vincent Vennin

The apparent difficulty in recovering classical nonlinear dynamics and chaos from standard quantum mechanics has been the subject of a great deal of interest over the last twenty years. For open quantum systems - those coupled to a…

Quantum Physics · Physics 2007-05-23 M. J. Everitt , T. D. Clark , P. B. Stiffell , J. F. Ralph , A. R. Bulsara , C. J. Harland

A generalization of the geometric measure of quantum discord is introduced in this article, based on Hellinger distance. Our definition has virtues of computability and independence of local measurement. In addition it also does not suffer…

Quantum Physics · Physics 2016-02-02 Hai-Tao Cui , Jun-Long Tian , Gui Yang

We introduce a Gaussian version of the entanglement of formation adapted to bipartite Gaussian states by considering decompositions into pure Gaussian states only. We show that this quantity is an entanglement monotone under Gaussian…

Quantum Physics · Physics 2009-11-10 M. M. Wolf , G. Giedke , O. Krueger , R. F. Werner , J. I. Cirac

Quantum discord quantifies how much Alice's system is disrupted after a measurement is performed on Bob's. Conceptually, this behavior acts the same way as quantum steering and we find that the discord grows with better steering from Bob to…

Quantum Physics · Physics 2015-03-05 Q. Y. He , Q. H. Gong , M. D. Reid

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

Mixtures of coherent states are commonly regarded as classical. Here we show that there is a quantum advantage in discriminating between coherent states in a mixture, implying the presence of quantum properties in the mixture, which are…

Quantum Physics · Physics 2018-02-26 I. Starshynov , J. Bertolotti , J. Anders

We study the correlation dynamics of a system composed of arbitrary numbers of qutrits interacting with a common environment. Initially, the system is assumed to be in a low dimensional subspace of the Hamiltonian called "decoherence-free…

Quantum Physics · Physics 2017-06-15 R. Sufiani , A. Pedram , M. Karimi