Quantum coherence and correlation dynamics of two-qubit system in spin bath environment**Project supported by the National Natural Science Foundation of China (Grant Nos. 61605225, 11704238, and 61772295), the Educational Science and Technology Program of Shandong Province, China (Grant No. J18KZ012), and the Natural Science Foundation of Shanghai (Grant No. 16ZR1448400).

Abstract

The quantum entanglement, discord, and coherence dynamics of two spins in the model of a spin coupled to a spin bath through an intermediate spin are studied. The effects of the important physical parameters including the coupling strength of two spins, the interaction strength between the intermediate spin and the spin bath, the number of bath spins and the temperature of the system on quantum coherence and correlation dynamics are discussed in different cases. The frozen quantum discord can be observed whereas coherence does not when the initial state is the Bell-diagonal state. At finite temperature, we find that coherence is more robust than quantum discord, which is better than entanglement, in terms of resisting the influence of environment. Therefore, quantum coherence is more tenacious than quantum correlation as an important resource.