Accelerating decay by multiple 2π pulses

We show how a control of the dynamics of a decay process can be achieved by the application of a series of $2\pi$ pulses on an auxiliary transition. The $2\pi$ pulse changes the phase of the ground state by $\pi$ 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 $2\pi$ pulse. Such an interference under suitable tailoring of the density-of-states of the bath and the time $\tau$ leads to accelerated decay.