论文标题
费米黄金法则的出现
Emergence of Fermi's Golden Rule
论文作者
论文摘要
费米（Fermi）的黄金法则（FGR）适用于限制，其中初始量子状态弱耦合到其他最终状态的{\ it continuum}重叠其能量的{\ it continuum}。在这里，我们调查了该限制发生的事情，其中最终状态集为离散，平均水平间距为非零；这个问题出现在许多最近研究的多体系统中。对于不同的对称类别，我们通过分析和/或数值来计算初始状态平均衰减的通用交叉，因为水平间距的变化，黄金规则以连续体的极限出现。在FGR给出的初始状态的指数衰减的校正中，在长期级别但非零级别间距的长期状态下的光谱形式。
Fermi's Golden Rule (FGR) applies in the limit where an initial quantum state is weakly coupled to a {\it continuum} of other final states overlapping its energy. Here we investigate what happens away from this limit, where the set of final states is discrete, with a nonzero mean level spacing; this question arises in a number of recently investigated many-body systems. For different symmetry classes, we analytically and/or numerically calculate the universal crossovers in the average decay of the initial state as the level spacing is varied, with the Golden Rule emerging in the limit of a continuum. Among the corrections to the exponential decay of the initial state given by FGR is the appearance of the spectral form factor in the long-time regime for small but nonzero level spacing.
