Quantum correlations of two qubits interacting with a macroscopic medium
We consider two particles of spin-\(1/2\) interacting with a one-dimensional \(N\)-spin array, which is an exactly solvable model. The dynamics of entanglement and quantum discord (QD) of the spins of the two particles is investigated by regarding the 1D \(N\)-spin array as the environment. It is found that although the entanglement may suffer a sudden death and a sudden birth in the evolution, it can neither be generated nor become larger than its initial value. Different from the entanglement dynamics, QD can be amplified and even be generated by the interaction between particles and the common environment. We also observe that QD decays asymptotically to zero and later experiences a rival when the average number of excitation in the 1D \(N\)-spin array becomes larger in the case of nonzero inter-distance between two particles.
KeywordsQuantum correlations Quantum discord Entanglement Quantum measurement process
This work was supported by NSFC Grants Nos. 11374095, 11422540, 11434011 and 11105050; NBRPC Grants No. 2012CB922103; Hunan Provincial Natural Science Foundation of China Grants Nos. 11JJ7001 and 12JJ1002.
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