Theory of Spin Relaxation for Arbitrary Time Scale.IV.Numerical Analysis and Simple Formulae
Theory of Spin Relaxation for Arbitrary Time Scale.IV.Numerical Analysis and Simple Formulae
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任意时间尺度的自旋弛豫理论四、数值分析和简单公式
DOI：
10.1143/jpsj.51.2728
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
F. Shibata
中科院分区：
文献类型：
--
作者：
Y. Hamano;F. Shibata
对横向弛豫过程和功率谱进行了详细的数值分析。这些都是用2个J函数的叠加来表示的[ J是自旋的大小]。对于初始条件远离平衡态的横向弛豫过程，这2个J函数的贡献，特别是在时间演化的早期阶段;在平衡附近，只有一个具有最小本征值的单一函数存活。由于非线性，在某些情况下，自旋横向分量的平均值会增强并达到最大值，并随着时间的推移而减小：这被认为是非线性效应引起的相位相干现象，超出了通常线性理论的范围。然而，功率谱基本上由单一函数确定，因此，即使对于任意J值，也可以从数值分析中推导出简单的规则。通过对“科尔-科尔”图的分析，揭示了这一现象的普遍性。
Detailed numerical analysis is made on the transverse relaxation process and on the power spectrum. These are expressed in terms of a superposition of 2 J -functions [ J the magnitude of spin]. For the transverse relaxation process with initial conditions far from equilibrium state, these 2 J functions do contribute especially at an early stage of time-evolution; near the equilibrium, only a single function with the minimum eigenvalue survives. Due to the nonlinearities, under certain circumstances, average of the transverse component of spins enhances itself to reach a maximum value and decreases as the time evolves: This is recognized as a phase coherence phenomenon induced by the nonlinear effect and is out of the scope of the usual linear theory. The power spectrum is, however, determined essentially by the single function and consequently, simple rules are deduced from the numerical analysis, even for arbitrary value of J . Analysis on the “Cole-Cole” diagram suggests a sort of universality in the re...