Motion of kinks in the ac-driven damped Frenkel-Kontorova chain

It is demonstrated that a spatially homogeneous ac drive applied to a chain of interacting particles in a periodic substrate potential may support progressive motion of a dislocation, or of a periodic array of them, in the presence of friction (which may be either weak or strong). The progressive motion of the periodic array of dislocations implies motion of the whole chain with some mean velocity. Although these effects usually disappear in the continuum limit, we also give an example of exotic continuum damped models where the ac-driven propagation of a kink is possible. Physical implementations of the effects predicted here are briefly discussed.