Formula that gives rate of transition from one state to a set of many other states, as function of perturbation strength and density of final states. https://e

Formula that gives rate of transition from one state to a set of many other states, as function of perturbation strength and density of final states. https://en.wikipedia.org/wiki/Fermi%27s_golden_rule https://en.wikipedia.org/wiki/Fermi%27s_golden_rule