COARSENING DYNAMICS OF THE XY MODEL

It is the conventional wisdom that the correlation length for the XY m odel with linear damping should asymptotically grow diffusively as the square root of time after a quench into the ordered phase. This impli es that the defect density rho should decay with time as rho is-propor tional-to t(-nu) with the scaling exponent nu=1. We present evidence, by numerically integrating the equations of motion for a two-dimension al XY model, for a logarithmic correction to this scaling which makes it difficult to reach the asymptotic regime nu=-d(1nrho)/d(1nt)=1. Eve n after the defect density has decayed by three orders of magnitude nu =0.91, which still deviates by 10% from the asymptotic value.