Abstract
We examined decay dynamics of various geometric quantum discords (GQDs) for two interacting qubits described by the Heisenberg XY model and further coupled independently to their respective thermal reservoirs. Compared to the case of noninteracting qubits, our results showed that decay rates of the GQDs can be retarded apparently by properly choosing system parameters of the interaction term. In the long-time limit, the asymptotic values of the GQDs are enhanced evidently by tuning anisotropy of the model and strength of the transverse magnetic field. We further illuminated the relations between different GQDs on characterizing quantum correlations, and observed multiple sudden change behaviors of their dynamics.
Highlights
Quantum correlations are long-standing concerns of the community of quantum mechanics, and they play an important role in the emerging field of quantum information science[1]
We have investigated dynamics of the quantum correlations for an exactly solvable dissipative model, aimed at revealing the interaction Hamiltonian on controlling quantum correlations
The measures of quantum correlations we adopted are the recently introduced trace distance discord (TDD), Hellinger distance discord (HDD), and Bures distance discord (BDD), and the central system we considered consists of two qubits which are coupled independently to their respective thermal reservoirs
Summary
We examined decay dynamics of various geometric quantum discords (GQDs) for two interacting qubits described by the Heisenberg XY model and further coupled independently to their respective thermal reservoirs. Quantum correlations in a system have been characterized and quantified from many different aspects, e.g., the widely-studied Bell-type nonlocality[2] and quantum entanglement[3] Apart from these progresses, a new framework for characterizing quantum correlations has been established by Henderson and Vedral[4], as well as by Ollivier and Zurek[5]. The relevant system consists of two qubits which are coupled via the Heisenberg XY interaction, and every qubit further interacts independently with a thermal reservoir Based on this setting, we calculated the geometric quantum discords (GQDs) by solving exactly the master equation describing evolution of these two qubits, and compared in detail their dynamical behaviors. The system parameter regions for which decay rates of the GQDs can be slowed down are identified, and singular behaviors of them such as the multiple sudden change (SC) phenomenon and the different orderings of quantum states imposed by different GQDs are observed
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