Conceptual design of a molecular shuttle

The effectiveness of low-dimensional thermal ratchets is shown to depend on the inertia of the carriers, that is on their mass. In an inertial ratchet (i) the suppression of the transport current at small noise-correlation times occurs through a more complicated mechanism than previously predicted in the zero-mass limit; (ii) the sign of the transport current may depend on the carrier mass. The conceptual design of a molecular motor is proposed, where the same carrier can shuttle massive cargos from one point to another along an assigned route. (C) 1998 Elsevier Science B.V.