Potts Model on the Bethe Lattice with Nonmagnetic Impurities in An External Magnetic Field

Abstract

We obtain a solution for the Potts model on the Bethe lattice in an external magnetic field with movable nonmagnetic impurities. Using the method of “pseudochaotic” impurity distribution (correlations in the positions of the impurity atoms for the neighboring sides vanish), we obtain a system of equations defining the first-order phase transition curve on the “temperature–external field” plane. We find the dependence of the endpoint of the phase transition line on the concentration of magnetic atoms.