Potts model with $q=4,6,$ and 8 states on Voronoi-Delaunay random lattice

TL;DR

This study uses Monte Carlo simulations to analyze phase transitions in 2D Potts models with 4, 6, and 8 states on Voronoi-Delaunay lattices, revealing both first- and second-order transitions depending on parameters.

Contribution

It introduces a model where the coupling varies with distance and explores phase transition types and critical exponents on a disordered lattice.

Findings

Second-order and first-order phase transitions depend on q and a.

Critical exponents were calculated for second-order transitions.

Cluster size distribution was studied for q=8.

Abstract

Through Monte Carlo simulations we study two-dimensional Potts models with $q=4, 6$ and 8 states on Voronoi-Delaunay random lattice. In this study, we assume that the coupling factor $J$ varies with the distance $r$ between the first neighbors as $J(r)\propto e^{-a r}$, with $a \geq 0$ . The disordered system is simulated applying the singler-cluster Monte Carlo update algorithm and reweigting technique. In this model both second-order and first-order phase transition are present depending of $q$ values and $a$ parameter. The critical exponents ratio $\beta/\nu$, $\gamma/\nu$, and $1/\nu$ were calculated for case where the second-order phase transition are present. In the Potts model with $q=8$ we also studied the distribution of clusters sizes.