Emerging criticality in the disordered three-color Ashkin-Teller model

TL;DR

This study shows that quenched disorder converts the first-order phase transition in the 2D three-color Ashkin-Teller model into a continuous transition, exhibiting Ising universality with universal logarithmic corrections, confirmed by large-scale Monte Carlo simulations.

Contribution

It provides the first large-scale simulation evidence that disorder induces Ising universality in the disordered Ashkin-Teller model, supporting renormalization-group predictions.

Findings

Disorder rounds the first-order transition to a continuous one.

Critical behavior matches the 2D Ising universality class.

Universal logarithmic corrections are observed.

Abstract

We study the effects of quenched disorder on the first-order phase transition in the two-dimensional three-color Ashkin-Teller model by means of large-scale Monte Carlo simulations. We demonstrate that the first-order phase transition is rounded by the disorder and turns into a continuous one. Using a careful finite-size-scaling analysis, we provide strong evidence for the emerging critical behavior of the disordered Ashkin-Teller model to be in the clean two-dimensional Ising universality class, accompanied by universal logarithmic corrections. This agrees with perturbative renormalization-group predictions by Cardy. As a byproduct, we also provide support for the strong-universality scenario for the critical behavior of the two-dimensional disordered Ising model. We discuss consequences of our results for the classification of disordered phase transitions as well as generalizations to other systems.