title: Nature of phase transitions in Axelrod-like coupled Potts models in two dimensions.
abstract: We study F coupled q-state Potts models in a two-dimensional square lattice. The interaction between the different layers is attractive to favor a simultaneous alignment in all of them, and its strength is fixed. The nature of the phase transition for zero field is numerically determined for F = 2,3. Using the Lee-Kosterlitz method, we find that it is continuous for F = 2 and q = 2, whereas it is abrupt for higher values of q and/or F. When a continuous or a weakly first-order phase transition takes place, we also analyze the properties of the geometrical clusters. This allows us to determine the fractal dimension D of the incipient infinite cluster and to examine the finite-size scaling of the cluster number density via data collapse. A mean-field approximation of the model, from which some general trends can be determined, is presented too. Finally, since this lattice model has been recently considered as a thermodynamic counterpart of the Axelrod model of social dynamics, we discuss our results in connection with this one.
authors.affiliation: Department of Mathematics and Namur Center for Complex Systems-naXys, University of Namur, rempart de la Vierge 8, B-5000 Namur, Belgium.
authors.forename: Yerali
authors.initials: Y
authors.lastname: Gandica
authors.affiliation: CFisUC, Department of Physics, University of Coimbra, P-3004-516 Coimbra, Portugal.
authors.forename: Silvia
authors.initials: S
authors.lastname: Chiacchiera