Phase separation in a weak first-order phase transition

Recent results on the phase transition in scalar field theory indicate that the strength of the transition is not a minor quantitative detail of the transition, but of considerable impact concerning the phase conversion mechanism. To see which phase conversion mechanism takes place depending on the strength of transition, we have simulated the q=5 state Potts model in two dimensions under an external magnetic field. Our results indicate that the phase conversion mechanism changes from nucleation-to-spinodal decomposition as the strength of the transition is weakened by increasing the external field.