标题： 激发电子种群非平衡多体物理中平均时间依赖性的松弛作用 显示英文标题

标题： The role of average time dependence on the relaxation of excited electron populations in nonequilibrium many-body physics

摘要： 我们研究了强关联电子种群在脉冲场非平衡激发后的运动方程，证明当格林函数没有平均时间依赖性时，种群不会发生变化。 我们展示了平均时间依赖性如何以最低阶进入运动方程，并描述了在长时间极限下控制电子种群弛豫过程的因素。 虽然这一结果表面上似乎是由任何稳态解所要求的，但证明是非平凡的，并提供了关于非平衡种群弛豫的新关键见解，这超越了它们通过由自能虚部决定的简单弛豫率热化，或它们可以通过具有时间依赖温度的准平衡条件和费米-狄拉克分布来描述的假设。 我们还讨论了这一结果对近似理论的影响，这些理论可能不满足运动方程中的精确关系。 显示英文摘要

摘要： We examine the exact equation of motion for the relaxation of populations of strongly correlated electrons after a nonequilibrium excitation by a pulsed field, and prove that the populations do not change when the Green's functions have no average time dependence. We show how the average time dependence enters into the equation of motion to lowest order and describe what governs the relaxation process of the electron populations in the long-time limit. While this result may appear, on the surface, to be required by any steady-state solution, the proof is nontrivial, and provides new critical insight into how nonequilibrium populations relax, which goes beyond the assumption that they thermalize via a simple relaxation rate determined by the imaginary part of the self-energy, or that they can be described by a quasi-equilibrium condition with a Fermi-Dirac distribution and a time-dependent temperature. We also discuss the implications of this result to approximate theories, which may not satisfy the exact relation in the equation of motion.