Exponential decay and resonances in a driven system

We study the resonance phenomena for time periodic perturbations of a Hamiltonian H on the Hilbert space L 2 ( R d ) . Here, resonances are characterized in terms of time behavior of the survival probability. Our approach uses the Floquet–Howland formalism combined with the results of L. Cattaneo, J.M. Graf and W. Hunziker on resonances for time independent perturbations.