Non-Markovian diffusion over potential barrier in the presence of periodic time modulation

The diffusive non-Markovian motion over a single-well potential barrier in the presence of a weak sinusoidal time-modulation is studied. We found non-monotonic dependence of the mean escape time from the barrier on a frequency of the periodic modulation that is character to the stochastic resonance phenomenon. The resonant acceleration of diffusion over the barrier occurs at the frequency inversely proportional to the mean first-passage time for the motion in the absence of the time-modulation.