Dc and ac soliton conductivity of disordered charge-density-wave systems and long Josephson junctions

A model of a commensurate charge-density-wave system with randomly distributed charged impurities, based on a driven damped or overdamped sine-Gordon equation with additional random terms, and a similar model of a driven damped or overdamped randomly inhomogeneous Josephson junction, are considered. A fundamental assumption is that the system contains phase solitons trapped by an effective random potential. With the increase of the dc drive, the solitons are released gradually. The corresponding I-V characteristics are found with regard to dissipative and radiative losses. A frequency dependence of the ac conductivity is found also