We substantially extend our relaxation theory for perturbed many-body quantum systems from [Phys. Rev. Lett. 124, 120602 (2020)] by establishing an analytical prediction for the time-dependent observable expectation values which depends on only two characteristic parameters of the perturbation operator: its overall strength and its range or band width. Compared to the previous theory, a significantly larger range of perturbation strengths is covered. The results are obtained within a typicality framework by solving the pertinent random matrix problem exactly for a certain class of banded perturbations and by demonstrating the (approximative) universality of these solutions, which allows us to adopt them to considerably more general classes of perturbations. We also verify the prediction by comparison with several numerical examples.

中文翻译：

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扰动量子多体系统的典型弛豫

我们从 [Phys. 牧师莱特。124, 120602 (2020)] 通过建立对时间相关的可观察期望值的分析预测，该值仅取决于扰动算子的两个特征参数：其整体强度及其范围或带宽。与之前的理论相比，涵盖了更大范围的扰动强度。结果是在典型性框架内通过精确解决特定类别的带状扰动的相关随机矩阵问题并通过证明这些解决方案的（近似）普遍性而获得的，这使我们能够将它们用于更一般的扰动类别。我们还通过与几个数值例子进行比较来验证预测。