Nonlinear Friction as a Mechanism of Directed Motion

摘要

A simple model (ratchet model) of occurrence of directed motion under the action of a zero-mean fluctuating force is proposed. The motion arises when the symmetry in the velocity space is violated by nonlinear friction. The mechanism of the directed motion is discussed qualitatively. Existence conditions of the motion are derived. The efficiency of conversion of the fluctuating random force to the directed motion is estimated.