Transport of overdamped Brownian particles in a two-dimensional asymmetric
tube is investigated in the presence of nonadiabatic periodic driving forces.
By using Brownian dynamics simulations we can find that the phenomena in
nonadiabatic regime differ from that in adiabatic case. The direction of the
current can be reversed by tuning the driving frequency. Remarkably, the
current as a function of the driving amplitude exhibits several local maxima at
finite driving frequency.Comment: 10 pages, 4 figure