NUMERICAL DIAGONALIZATION OF THE GLAUBER DYNAMICS ABOVE AND BELOW THE TRANSITION-TEMPERATURE

We numerically diagonalize the time-evolution matrix for the order-parameter-nonconserving Glauber dynamics on the two-dimensional square lattice up to a 25-spin system. The relaxation rate and the weight for the spin autocorrelation function are calculated above and below the transition temperature in order to examine the assumptions used by Takano et al. [Phys. Rev. B 37, 3716 (1988)], who predicted stretched-exponential decay for the spin autocorrelation function below the transition temperature. The relaxation mode structure below the transition temperature is also discussed.