Nature of phase transitions in Axelrod-like coupled Potts models in two dimensions

TL;DR

This study investigates phase transitions in coupled Potts models on a 2D lattice, revealing continuous transitions for low parameters and abrupt ones for higher, with implications for social dynamics models.

Contribution

It provides a numerical analysis of phase transition types in coupled Potts models and connects these findings to social dynamics models like Axelrod.

Findings

Continuous transition for F=2, q=2

Abrupt transition for higher q and F

Fractal dimension of clusters analyzed

Abstract

We study $F$ coupled $q$-state Potts models in a two-dimensional square lattice. The interaction between the different layers is attractive, to favour 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.