Stable spins in the zero temperature spinodal decomposition of 2D Potts models

We present the results of zero temperature Monte Carlo simulations of the q-state Potts model on a square lattice with either four or eight neighbors, and for the triangular lattice with six neighbors. In agreement with previous works, we observe that the domain growth process gets blocked for the nearest-neighbor square lattice when q is large enough, whereas for the eight neighbor square lattice and for the triangular lattice no blocking is observed. Our simulations indicate that the number of spins which never flipped from the beginning of the simulation up to time t follows a power law as a function of the energy, even in the case of blocking. The exponent of this power law varies from less than 1/2 for the Ising case (q = 2) to 2 for q --> infinity and seems to be universal. The effect of blocking on this exponent is invisible at least up to q = 7.