Ratchet effect in an underdamped periodic potential and its characterisation

Ratchet effect in a driven underdamped periodic potential system is studied. The presence of a space dependent and periodic friction coefficient, but with a phase difference with the symmetric periodic potential is shown to generate substantial ratchet current. The ratchet performance is characterised in terms of the various parameters of transport. The performance of this ratchet is compared with a ratchet with an underlying periodic and asymmetric potential. It is shown that an optimum combination of inhomogeneity in the system and asymmetry of the potential can substantially enhance the performance of an underdamped ratchet.