Decay of a quantum discrete state resonantly coupled to a quasi-continuum set of states

Abstract

The irreversible exponential decay from a discrete state to the continuum, described by time-dependent perturbation theory, is a difficult task in quantum mechanics learning, because of the complexity of the mathematical tools involved. An easy model which consists in analyzing the decay from a discrete state to a quasi-continuum set of states is developed. The mathematics required to understand the model are easy, allowing for a deep analysis of the model. The physical conditions required to describe the transition produced by a sinusoidal perturbation by an exponential decay are easily deduced.