Disorder induced control of discrete soliton ratchets

We demonstrate that directed transport of topological solitons in damped, biharmonically driven Frenkel-Kontorova chains can be strongly enhanced by introducing suitable phase disorder into the asymmetric periodic driving. From a collective coordinate formalism, we theoretically deduce an effective deterministic equation of motion governing the dynamics of the soliton center-of-mass for which we predict the dependence of maximal soliton drift on disorder strength according to recently proposed general scaling laws concerning directed transport induced by symmetry breaking of temporal forces. We find that these results are in excellent agreement with those of computer simulations of the original Frenkel-Kontorova chains.