Symmetry breaking and AC-driven dynamics of solitons
We report on the possibility of unidirectional motion of a topological soliton in a dissipative AC-driven Klein-Gordon equation. This motion is due to breaking of certain space-time symmetries. It can be achieved by the proper choice of the potential or the AC force. Tha same symmetry considerations are applied to the discrete Klein-Gordon equation. We formulate the necessary symmetry conditions for the AC force and confirm them with the first order perturbation theory and numerical simulations.