Anomalous dynamic response in the two-dimensional lattice Coulomb gas model: Effects of pinning

It is demonstrated through Monte Carlo simulations that the one-component lattice Coulomb gas model in two dimensions under certain conditions displays features of an anomalous dynamic response. We suggest that pinning, which can either be due to the underlying discrete lattice or induced by disorder, is an essential ingredient behind this anomalous behavior. The results are discussed in relation to other situations where this response type appears, in particular the two-component neutral Coulomb gas below the Kosterlitz-Thouless transition, as well as in relation to other findings from theory, simulations, and experiments on superconductors.