Witnessing quantum discord in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>2</mml:mn><mml:mo>×</mml:mo><mml:mi>N</mml:mi></mml:mrow></mml:math>systems

Bylicka, Bogna; Chruściński, Dariusz

doi:10.1103/physreva.81.062102

Cited by 103 publications

(79 citation statements)

References 39 publications

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“…Nevertheless, one can swap the role of A and B and get another expression [28] for quantum discord as…”

Section: Quantum Discordmentioning

confidence: 99%

Quantum discord for a two-parameter class of states in 2⊗dquantum systems

Ali¹

2010

J. Phys. A: Math. Theor.

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Abstract.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 processing. Quantum discord has been evaluated explicitly only for certain class of two-qubit states. We extend the previous studies to 2 ⊗ d quantum systems and derive an analytical expression for quantum discord for a two-parameter class of states for d ≥ 3. We compare quantum discord, classical correlation, and entanglement for qubit-qutrit systems to demonstrate that different measures of quantum correlation are not identical and conceptually different.

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“…Nevertheless, one can swap the role of A and B and get another expression [28] for quantum discord as…”

Section: Quantum Discordmentioning

confidence: 99%

Quantum discord for a two-parameter class of states in 2⊗dquantum systems

Ali¹

2010

J. Phys. A: Math. Theor.

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“…When considering an initial entangled state exposed to * E-mail: huyaohua1@sina.com local noisy environments, the entanglement may decrease abruptly and nonsmoothly to zero in a finite time, which is called entanglement sudden death (ESD) [5][6][7]. However, recent researches have shown that entanglement is not the only measure of quantum correlation, and a new but promising candidate is the quantum discord [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Quantum discord, first introduced by Ollivier and Zurek [16], is defined as the difference between the total correlation and the classical correlation with the following expression (ρ AB ) = (ρ AB ) − (ρ AB )…”

Section: Introductionmentioning

confidence: 99%

Quantum discord between two moving two-level atoms

Hu¹,

Mao-Fa

2011

Open Physics

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Ê Ú ¼¿ Å Ö ¾¼½½ ÔØ ¾ Ù Ù×Ø ¾¼½½ ×ØÖ ØConsidering a double JC model, this paper investigates the quantum discord dynamics of two isolated moving two-level atoms each interacting with a single-mode thermal cavity field, and studies the effect of the atomic motion and the field-mode structure on quantum discord. The results show that, on the one hand the quantum discord evolves periodically with time and the periods are affected by the atomic motion and the field-mode structure; on the other hand, the quantum discord still can capture the quantum correlation between the two atoms when the entanglement is zero. It is interesting to note that the quantum discord can be effectively preserved by controlling the field-mode structure parameter.

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“…Recently various methods to detect zero-discord [28][29][30] have been proposed for a given state as well as for an unknown state [31]. Moreover, it is found that vanishing quantum discord is related to the complete positivity of a map [32] and the local broadcasting of quantum correlations [15].…”

Section: Introductionmentioning

confidence: 99%

Asymptotic dynamics of quantum discord in open quantum systems

Berrada

Eleuch

Hassouni

2011

J. Phys. B: At. Mol. Opt. Phys.

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To cite this version: It is well known that quantum entanglement makes possible certain tasks in quantum information theory. However, there are also quantum tasks that display the quantum advantage without entanglement. Distinguishing classical and quantum correlations in quantum systems is therefore of both practical and fundamental importance. Realistic quantum systems are not closed and therefore it is important to study the various correlations when the system loses its coherence due to interactions with the environment. In this paper, we study in detail the dynamics of different kinds of correlations, classical correlation, quantum discord, and entanglement in open quantum systems, in particular a two-qubit system evolving under quantum dynamical semigroups of Kossakowski-type of completely positive maps. In such an environment classical and quantum correlations can even persist asymptotically. By analytic and numerical analysis, we find that the quantum discord is larger than the classical correlation for asymptotic states. Furthermore, we show that the quantum discord is more resistant to the action of the environment than the quantum entanglement and it can persist even in the asymptotic long-time regime.

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Witnessing quantum discord in2×Nsystems

Cited by 103 publications

References 39 publications

Quantum discord for a two-parameter class of states in 2⊗dquantum systems

Quantum discord for a two-parameter class of states in 2⊗dquantum systems

Quantum discord between two moving two-level atoms

Asymptotic dynamics of quantum discord in open quantum systems

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