Direction Depended Transport in a Hamiltonian Ratchet induced by a time-Dependent Dissipative Impurity

Ratchets are known to induce directed transport, but in hermitean systems transport strongly depends on the initial conditions which can reduce the ratchet effect dramatically. In this work we both theoretically and experimentally study directed transport in a fast Hamilton ratchet and show that a time-depended dissipative impurity can be used as a direction depended filter. We calculate asymmetric transmission coefficients using Floquet-S-matrix theory and find parameter regions where we the efficiency of the filter is almost ideal.