将电子自由度积掉后，我们得到了描述核自旋的有效作用量以及核自旋的自旋波传播子。

After integrating out the electron degrees of freedom, we derive the effective action describing the nuclear spins and the propagator for the spin wave.

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第三章从一个四自由度弹簧振子的振动分析问题提出耦合单元的概念，建立了多转子系统振动分析的整体传递矩阵法；

In the third part, the concept of coupling element is derived from the vibration analysis of a four-degree spring-oscillator system, and a whole transfer matrix method is developed on the basis of it.

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该方法不是从第一原理出发，因为耗散环境应该被看成是自由度为无限维的谐振子或原子系统，对它的求解最好的方式是求解约化密度矩阵方程。

This method is not from the first principle. A better approach is based on the reduced density matrix, which eliminate the infinite number of the freedoms of the dissipative environment.

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