Asymptotic dynamics of quantum discord in open quantum systems

Abstract

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.

Tailoring Quantum Correlations of a Coupled Central Two Qubits Soaked in a Finite Temperature Antiferromagnetic Environment with Frequency Gap

“…This is from the fact that, during the dissipative time evolution even without quantum entanglement, the correlations introduced by the environment are transferred to the two central qubits, producing a finite quantum discord. We equally notice from Figure 7 that discord is larger than classical correlation, a scenario similarly observed in [27]. This results provide the description of the behavior of the classical and quantum correlations and their robustness under the decoherence process.…”

“…Quantum discord is introduced as the difference between the total correlations and the classical correlation and has been evaluated in many works [23]- [27]. In order to discuss the time variation of quantum correlations other than entanglement of the coupled two qubits system bathed in the model of the antiferromagnetic environment, we will only provide results without further derivations since we are concerned with two-qubit X state that has been explicitly derived in [24].…”

Effect of the phase damping of two qubits on both the quantum discord and non-local correlation

“…By using GMQD and MIN, the quantum correlation of two qubits is studied in [21,22]. While the quantum correlations and QD with and GMQD is studded in [23]. Also, the pairwise correlations, including QD and GMQD is studded in [24].…”

Information Entropy and Information Granulation-based Uncertainty Measures in Incomplete Information Systems

“…The concept of entropy, originally defined by Shannon in 1948 for communication theory, gives a measure of the uncertainty about the structure of a system [14]. It has been a useful mechanism for characterizing uncertainty in a great diversity of modes and applications [15,16,17,18]. Shannon's entropy and its variants have been used to measure the uncertainty in rough set theory, and information interpretation of rough set theory was given in [9,10,19].…”