Non-Markovian decay of an atom coupled to a reservoir: Modification by frequency modulation - art. no. 025802

A two-level atom coupled to a reservoir with Lorentzian spectral response f unction is considered. It is shown that if the free oscillations of the ato mic dipole are suitably modulated by an external field, then the dynamics o f the spontaneous decay can be strongly modified. As a result, the probabil ity of finding the atom in an excited state can be large even for very long times. This is because the frequency modulation may lead to both effective detuning of the atom from the resonance with reservoir modes and to effect ive cancellation of the coupling between the atom and the reservoir. Non-Ma rkovian features of the reservoir are found to be essential for this effect to be observable. Conditions of experimental verifications are provided.