Space-time propagator and exact solution for wave equation in a layered system

Abstract

Exact space-time propagator for the wave (second-order in time) equation in a layered ysstem, made up of a layer sandwiched between two other different semi-infinite layers, is obtained by means of the multiple scattering theory (MST) approach. The MST approach is made possible due to obtained effective potentials localized at interfaces and responsible for reflection from and propagation through them. The obtained spacetime propagator exactly solves the considered wave equation for any initial value and allows for following in time the processes of reflection and transmission. The solution for an initial Gaussian wave packet is obtained, analyzed, numerically visualized and discussed for the case of the perpendicular-to-interfaces incoming wave. In particular, the contribution of the backward-moving components of the wave packet is revealed.