The phenomenological Landau theory of the spin precession has been used to reproduce the out-of-equilibrium properties of many magnetic systems. However, such an approach suffers from some serious limitations. The main reason is that the spin and the angular momentum of the atoms are described by the classical theory of the angular momentum. We derive a discrete model that extends the Landau theory to the quantum mechanical framework. Our approach is based on the application of the quantification procedure to the classical Hamiltonian of an array of interacting spins. The connection with the classical dynamics is discussed.

中文翻译：

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相互作用自旋的量子原子方法

自旋进动的现象学朗道理论已被用来重现许多磁性系统的失衡性质。但是，这种方法受到一些严重的限制。主要原因是原子的自旋和角动量由角动量的经典理论描述。我们导出了一个离散模型，该模型将Landau理论扩展到了量子力学框架。我们的方法是基于将量化过程应用于一系列相互作用的自旋的经典哈密顿量。讨论了与经典动力学的联系。