- We show how a control of the dynamics of a decay process can be achieved by the application of a series of 2 pulses on an auxiliary transition. The 2 pulse changes the phase of the ground state by while leaving the phase of the excited state unaltered. This produces quantum interferences between the transition amplitudes for evolution in the short interval, just before and after the 2 pulse. Such an interference under suitable tailoring of the density-of-states of the bath and the time leads to accelerated decay. 2001 The American Physical Society.