Multicanonical simulations of the 2D spin-$1$ Baxter-Wu model in a crystal field

TL;DR

This study uses multicanonical simulations to analyze the phase transition behavior of the 2D spin-1 Baxter-Wu model in a crystal field, revealing its universality class and finite-size effects near critical points.

Contribution

It introduces a parallel multicanonical algorithm to study the 2D spin-1 Baxter-Wu model and identifies its universality class and finite-size effects.

Findings

Transition belongs to the 4-state Potts universality class.

Finite-size effects become more pronounced near the pentacritical point.

First-order-like effects observed in finite-size scaling analysis.

Abstract

We investigate aspects of universality in the two-dimensional (2D) spin-$1$ Baxter-Wu model in a crystal field $\Delta$ using a parallel version of the multicanonical algorithm employed at constant temperature $T$. A detailed finite-size scaling analysis in the continuous regime of the $\Delta-T$ phase diagram of the model indicates that the transition belongs to the universality class of the $4$-state Potts model. The presence of first-order-like finite-size effects that become more pronounced as one approaches the pentacritical point of the model is highlighted and discussed.