The Dynamical Evolution of Quantum Correlations in the Two Isolate Spin Particles Coupled to a Common Bath.

We study the dynamical evolution of quantum correlations between two central spins independently coupled to a common bath, which are represented by quantum entanglement and quantum discord. According to the results of the exact solution, we show that quantum discord is more robust and includes richer correlation than quantum entanglement due to the nonvanishing quantum correlation in the region of entanglement death, i.e., the separable states maybe contain nonclassical correlations. We discuss the effects of the intrinsic properties of the bath on quantum correlation between the two central spins in the XY and XXZ model baths. At the low temperature, the central system can keep the good quantum correlation. With the more spin number in the bath, the dynamical evolution of quantum correlation can be bounded with the small oscillation and finally approaches a stable value. In addition, we find that the interaction between the central spins and the bath in the z direction has the significant effects on quantum correlation of the central spin system. [ABSTRACT FROM AUTHOR]