量子磁体中 Lindbladian 耗散导致的 Landau-Lifshitz 阻尼
Landau-Lifshitz damping from Lindbladian dissipation in quantum magnets
AI总结：
本文在局域平均场理论中从 Lindbladian 耗散系统地推导出 Landau-Lifshitz 动力学，并将其扩展到磁化强度长度，假设耗散瞬时适应非平衡哈密顿量以降低期望值。
AI中文摘要：
迄今为止，唯象的经典 Landau-Lifshitz (LL) 磁序阻尼尚未与 Lindbladian 形式主义的量子耗散理论建立概念上的联系，这对于蓬勃发展的磁动力学研究而言是不令人满意的。本文表明，在弱外场的局域平均场理论中，LL 动力学可以从 Lindbladian 动力学系统地推导出来。该推导还将 LL 动力学从取向 $\vec{m}/|\vec{m}|$ 扩展到磁化强度长度 $|\vec{m}|$。一个关键假设是，Lindbladian 耗散瞬时适应非平衡 $H(t)$ 以降低其期望值。
英文摘要：
As of now, the phenomenological classical Landau-Lifshitz (LL) damping of magnetic order is not conceptually linked to the quantum theory of dissipation of the Lindbladian formalism which is unsatisfactory for the booming research on magnetic dynamics. Here, it is shown that LL dynamics can be systematically derived from Lindbladian dynamics in a local mean-field theory for weak external fields. The derivation also extends the LL dynamics beyond the orientation $\vec{m}/|\vec{m}|$ to the length $|\vec{m}|$ of the magnetization. A key assumption is that the Lindbladian dissipation adapts to the non-equilibrium $H(t)$ instantaneously to lower its expectation value.
