Phase transition in a two-dimensional three-state Potts model with the addition of an infinite-range coupling

Abstract

The authors study the two-dimensional three-state Potts model with nearest-neighbour and infinite-range interaction at different values of the two coupling constants. They analyse the intermediate region between the pure infinite-range interaction and the nearest-neighbour one. They find a first-order phase transition for all values of the coupling constants on the coexistence curve except for the pure nearest-neighbour interaction where Baxter's result holds. A Monte Carlo simulation which supports the theoretical expectation is expounded.