研究了处在非均匀磁场中的两粒子Ising系统,在考虑DM相互作用情况下,其量子失协(QD)随时间的演化问题.对于初始处于Werner态的系统,详细分析了在随时间演化过程中DM相互作用、不均匀磁场的不均匀度、初态的纯度等因素对量子失协和量子纠缠的影响.通过比较可以发现,两者在很大程度上保持着相似的变化规律,最明显的不同在于演化过程中,在有限的时间内量子失协并不会消失,但是量子纠缠却会出现突然死亡现象(ESD).这一明显不同的特征表明量子失协比量子纠缠具有更大的应用空间,通过控制外部条件,可以很好地控制量子失协随时间的演化过程.
The dynamics of quantum discord (QD) is investigated in the two-qubit Ising system in an inhonogeneous magnetic field with the Dzialoshinskii-Moriya (DM) interaction. The system is initially prepared in the Werner state,and the effects of the DM interaction,degree of inhomogeneous magnetic field and purity of the initial state on QD and entanglement iu the evolution process are analyzed in detail.By comparison,it is found that both the quantum discord and entanglement take similar behaviors to a large extent,and QD does not vanish in the finite time,but the phenomenon of entanglement sudden death (ESD)appears during the evolution process.This difference shows that the quantum discord is more practical than the entanglement to evaluate the quantum correlation.These effects also indicate that one can control the quantum discord of the system by some exterior conditions.
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