Radiative decay of nondispersive wave packets

We study the decay of nondispersive electronic wave packets in strongly driven hydrogen atoms, which are coupled to the atomic continuum and to the vacuum modes of the electromagnetic field. A novel implementation of complex scaling allows to derive a master equation that incorporates the interplay of the coherent and the incoherent decay process. Ample numerical data predict a crossover from ionization via chaos-assisted tunneling to radiative decay, at experimentally accessible Rydberg levels