摘要
Taking into account the intrinsic decoherence, we have investigated quantum correlations in a two-qubit Heisenberg XX model when a nonuniform magnetic field is included. We compare entanglement measured by entan- glement of formation, quantum discord and measurement-induced measurement （MID） and illustrate their different characteristics. Quantum discord and MID show the same features and always exist even though there is no entangle- ment in the long time limit. In the time evolution, quantum discord could be generated or enhanced to the stable value, while MID just decreases to the stable value.
基金
Supported by "the Fundamental Research Funds for the Central Universities" of China University of Mining and Technology under Grant No.2012QNA37
the National Natural Science Foundation of China under Grant No.11375168
