Semiclassical Asymptotics of the Solution to the Cauchy Problem for the Schrödinger Equation with a Delta Potential Localized on a Codimension 1 Surface

We describe the semiclassical asymptotics of the solution to the Cauchy problem for the Schrödinger equation with a delta potential localized on a codimension $1$ surface. The initial condition represents a rapidly oscillating wave packet. We show that the asymptotics is expressed in terms of the Maslov canonical operator on a pair of Lagrangian manifolds in the extended phase space; the form of the delta potential defines a mapping between these manifolds that describes the reflection and scattering of the wave packet.