Decay of a Bound State under a Time-Periodic Perturbation: a Toy Case
  We study the time evolution of a three dimensional quantum particle, initially in a bound state, under the action of a time-periodic zero range interaction with ``strength'' (\alpha(t)). Under very weak generic conditions on the Fourier coefficients of (\alpha(t)), we prove complete ionization as (t \to \infty). We prove also that, under the same conditions, all the states of the system are scattering states. 
Michele Correggi, Gianfausto Dell'Antonio