A delta-kicked Brownian rotor

We study the evolution of a delta-kicked Fokker-Planck equation which is a certain limiting case of a driven Brownian rotor with large friction. The time evolution of the rotor is given by a Floquet map in which the effects of diffusion and of the kick are decoupled. For the case where absorbing boundaries are introduced, we show the mechanism causing an abrupt drop in the average survival time as the kick strength is increased.