Anomalous relaxation in the XY gauge glass

To study relaxation dynamics of the two-dimensional XY gauge glass, we integrate directly the equations of motion and investigate the energy function. As usual, it decays exponentially at high temperatures; at low but nonzero temperatures, it is found to exhibit an algebraic relaxation. We compute the relaxation time τ as a function of the temperature T and find that the rapid increase of τ at low temperatures is well described by τ∼(T-T_g)^-b with T_g=0.22±0.02 and b=0.76±0.05, which strongly suggests a finite-temperature glass transition. The decay of vorticity is also examined and explained in terms of a simple heuristic model, which attributes the fast relaxation at high temperatures to annihilation of unpinned vortices.