论文标题
从电荷到自旋：类比和量子传输系数的差异
From charge to spin: analogies and differences in quantum transport coefficients
论文作者
论文摘要
我们回顾了在质量质量系统中电荷传输和自旋的数学理论的最新结果。重点是传输系数等电导率和电导率。至于前者，它们是根据非平衡近平稳状态（NEAS）的适当期望计算的，这是由于外部电场对平衡状态的扰动而产生的。对于电荷运输，通常会恢复通常的双重交换器Kubo公式（也超出了线性响应），但我们获得了适当定义的自旋电导率的公式，这些旋转电导率仍然显式但更多地涉及。这些公式中的某些“库邦样”术语也被证明与对旋转电导的相应贡献一致。除此之外，我们采用了类似的技术来显示新的结果，即，即使在没有保守的自旋系统中，也没有旋转扭矩的产生，那就是旋转扭矩操作员对荷兰的期望比扰动场强度的任何强度都更快。
We review some recent results from the mathematical theory of transport of charge and spin in gapped crystalline quantum systems. The emphasis will be in transport coefficients like conductivities and conductances. As for the former, those are computed as appropriate expectations of current operators in a non-equilibrium almost-stationary state (NEASS), which arises from the perturbation of an equilibrium state by an external electric field. While for charge transport the usual double-commutator Kubo formula is recovered (also beyond linear response), we obtain formulas for appropriately-defined spin conductivities which are still explicit but more involved. Certain "Kubo-like" terms in these formulas are also shown to agree with corresponding contributions to the spin conductance. In addition to that, we employ similar techniques to show a new result, namely that even in systems with non-conserved spin there is no generation of spin torque, that is the spin torque operator has an expectation in the NEASS which vanishes faster than any power of the intensity of the perturbing field.
