Survival probability of multibarrier resonance systems: Exact analytical approach

We study the properties of the survival probability in multibarrier resonance systems using an exact analytical approach that involves a representation in terms of the resonance poles and resonant states of the system. We find a mechanism that modifies the usual exponential decaying regime into a nonexponential decay behavior of the survival probability. This mechanism corresponds to the decay of Rabi oscillations originating from transitions among the closely lying resonances characterizing the energy spectra of multibarrier resonance systems