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The dynamics of entanglement and quantum discord for qubit-qutrit systems are studied in the presence of phase damping and amplitude damping noises. Both one way and two couplings of the marginal systems with the environments are…

Quantum Physics · Physics 2016-12-22 Salman Khan , Ishaq Ahmad

Quantum measurements necessarily disturb the state of physical system. Once we perform a complete measurement, the system undergoes decoherence and loses its coherence. If there is no disturbance, the state retains all of its coherence. It…

Quantum Physics · Physics 2018-10-10 Gautam Sharma , Arun Kumar Pati

Quantum systems in mixed states can be unentangled and yet still correlated in a way that is not possible for classical systems. These correlations can be quantified by the quantum discord and might provide a resource for certain…

Quantum Physics · Physics 2014-05-26 B. P. Lanyon , P. Jurcevic , C. Hempel , M. Gessner , V. Vedral , R. Blatt , C. F. Roos

We study bipartite quantum discord as a manifestation of a multipartite entanglement structure in the tripartite purified system. In particular, we find that bipartite quantum discord necessarily manifests itself in the presence of both…

Quantum Physics · Physics 2013-07-29 Eric G. Brown , Eric J. Webster , Eduardo Martin-Martinez , Achim Kempf

Quantum discord characterizes "non-classicality" of correlations in quantum mechanics. It has been proposed as the key resource present in certain quantum communication tasks and quantum computational models without containing much…

Quantum Physics · Physics 2010-11-04 Borivoje Dakic , Vlatko Vedral , Caslav Brukner

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

When a quantum system is divided into two local subsystems, measurements on the two subsystems can exhibit correlations beyond those possible in a classical joint probability distribution; these are partially explained by entanglement, and…

Quantum Physics · Physics 2019-06-17 Aaron Szasz

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 show that the phenomenon of frozen discord, exhibited by specific classes of two-qubit states under local nondissipative decoherent evolutions, is a common feature of all known bona fide measures of general quantum correlations. All…

Quantum Physics · Physics 2013-07-23 Benjamin Aaronson , Rosario Lo Franco , Gerardo Adesso

We revisit the upper bound of quantum discord given by the von Neumann entropy of the measured subsystem. Using the Koashi-Winter relation, we obtain a trade-off between the amount of classical correlation and quantum discord in the…

Quantum Physics · Physics 2015-06-03 Zhengjun Xi , Xiao-Ming Lu , Xiaoguang Wang , Yongming Li

We introduce the notion of quantum dissension for a three-qubit system as a measure of quantum correlations. We use three equivalent expressions of three-variable mutual information. Their differences can be zero classically but not so in…

Quantum Physics · Physics 2012-04-05 Indranil Chakrabarty , Pankaj Agrawal , Arun K. Pati

We analyze and show experimental results of the conditional purity, the quantum discord and other related measures of quantum correlation in mixed two-qubit states constructed from a pair of photons in identical polarization states. The…

Quantum Physics · Physics 2016-11-23 L. Rebón , R. Rossignoli , J. J. M. Varga , N. Gigena , N. Canosa , C. Iemmi , S. Ledesma

Quantum discord is usually referred to as a measure for quantum correlations. In the search of the fundamental resource to gain a quantum advantage in quantum information applications, quantum discord is considered a promising candidate. In…

Quantum Physics · Physics 2012-06-04 Manuel Gessner , Elsi-Mari Laine , Heinz-Peter Breuer , Jyrki Piilo

Quantum phase transitions of the transverse Ising and antiferromagnetic XXZ spin S=1/2 chains are studied using quantum discord. Quantum discord allows the measure of quantum correlations present in many-body quantum systems. It is shown…

Strongly Correlated Electrons · Physics 2008-12-17 Raoul Dillenschneider

Quantum discord, a kind of quantum correlation based on entropic measures, is defined as the difference between quantum mutual information and classical correlation in a bipartite system. Procedures are available for analytical calculation…

Quantum Physics · Physics 2018-07-26 A. R. P. Rau

Quantum discord witnesses the nonclassicality of quantum states even when there is no entanglement in these quantum states. This type of quantum correlation also has some interesting and significant applications in quantum information…

Quantum Physics · Physics 2015-05-19 Mazhar Ali

We characterize the behavior of quantum correlations under the influence of local noisy channels. Intuition suggests that such noise should be detrimental for quantumness. When considering qubit systems, we show for which channel this is…

Quantum Physics · Physics 2011-10-18 Alexander Streltsov , Hermann Kampermann , Dagmar Bruß

Non-classical correlations play a crucial role in the development of quantum information science. The recent discovery that non-classical correlations can be present even in separable (unentangled) states has broadened this scenario. This…

We propose a global measure for quantum correlations in multipartite systems, which is obtained by suitably recasting the quantum discord in terms of relative entropy and local von Neumann measurements. The measure is symmetric with respect…

Quantum Physics · Physics 2011-11-28 C. C. Rulli , M. S. Sarandy

We study analytically the dynamic behaviors of quantum correlation measured by quantum discord between two uncoupled qubits, which are immersed in a common Ohmic environment. We show that the quantum discord of the two noninteracting qubits…

Quantum Physics · Physics 2015-05-19 Ji-Bing Yuan , Jie-Qiao Liao , Le-Man Kuang