Critical behavior of pinned charge-density waves below the threshold for sliding

Numerical results on the static critical behavior of a collective-pinning model of charge-density waves are presented. Distinct critical behaviors are found for irreversible (typical) and reversible approaches to the threshold for sliding. From the size dependence of the threshold fields and polarizations, at least two distinct finite-size-scaling correlation-length exponents are identified. New analytic results on the general behavior of this model both above and below threshold are reported, including the uniqueness of the sliding state.