Collective modes in a coupled ratchet model

We analyze a system consisting in many elastically coupled particles that are placed in a periodic ratchet potential on a ring. The system is assumed to be overdamped and driven by an external potential that is periodic both in space and time. The symmetries of the model allow to study the orbits with and without the presence of thermal fluctuations and for a changing intensity of the elastic coupling and the external driving force. We investigate the dependence of the transport current on the intensity of the elastic interaction. The direction of the current may be understood as resulting from the competition of collective transport modes in opposite directions and presents an inversion as the elastic coupling is increased.