Universal amplitude ratios in the 2D four-state Potts model

We present a Monte Carlo study of various universal amplitude ratios of the two-dimensional q = 4 Potts model. We simulated the model close to critica lity in both phases taking care to keep the systematic errors, due to finit e size effects and logarithmic corrections in the scaling functions, under control. Our results are compatible with those recently obtained using the form-factor approach and with the existing low temperature series for the m odel. (C) 1999 Elsevier Science B.V. All rights reserved.