Multiple quantum spin dynamics of entanglement
Multiple quantum spin dynamics of entanglement
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DOI：
10.1103/physreva.68.052306
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发表时间：
2003-11-01
影响因子：
2.9
通讯作者：
Doronin, SI
中科院分区：
文献类型：
--
作者：
Doronin, SI
基于多量子(MQ)核磁共振自旋动力学的精确可解模型，研究了纠缠动力学。结果表明，固体中耦合核自旋系统的MQ相干性的时间演化与量子纠缠的动力学直接相关。我们解析地研究了偶极-偶极相互作用耦合的两自旋和三自旋系统的纠缠态动力学。在这种情况下，量子纠缠的动力学唯一地由二阶MQ相干的时间演化决定。描述固体中MQ动力学的密度矩阵的实部负责零级的MQ相干，而它的虚部负责二级的MQ相干。因此，可以得出结论，纠缠的动力学与从密度矩阵的实部到虚部的跃迁有关，反之亦然。找到了推广Greenberger-Horne-Zeilinger(GHz)态和W态的纯态。对于三体系统，分析了该态纠缠的不同度量。
The dynamics of entanglement is investigated on the basis of exactly solvable models of multiple quantum (MQ) NMR spin dynamics. It is shown that the time evolution of MQ coherences of systems of coupled nuclear spins in solids is directly connected with dynamics of the quantum entanglement. We studied analytically the dynamics of entangled states for two- and three-spin systems coupled by the dipole-dipole interaction. In this case the dynamics of the quantum entanglement is uniquely determined by the time evolution of MQ coherences of the second order. The real part of the density matrix describing MQ dynamics in solids is responsible for MQ coherences of the zeroth order while its imaginary part is responsible for the second order. Thus, one can conclude that the dynamics of the entanglement is connected with transitions from the real part of the density matrix to the imaginary one, and vice versa. A pure state which generalizes the Greenberger-Horne-Zeilinger (GHZ) and W states is found. Different measures of the entanglement of this state are analyzed for tripartite systems.