Laser-assisted decay of quasistationary states

The effects of intense electromagnetic fields on the decay of quasistationary states are investigated theoretically. We focus on the parameter regime of strong laser fields and nonlinear effects where an essentially nonperturbative description is required. Our approach is based on the imaginary time method previously introduced in the theory of strong-field ionization. Spectra and total decay rates are presented for a test case and the results are compared with exact numerical calculations. The potential of this method is confirmed by good quantitative agreement with numerical results.