Pseudo-Phase Transitions of Ising and Baxter-Wu Models in Two-Dimensional Finite-Size Lattices

TL;DR

This paper investigates pseudo-phase transitions in finite-size 2D Ising and Baxter-Wu models using microcanonical analysis, revealing the order of transitions and identifying higher-order transitions, thus enhancing understanding of finite-size effects.

Contribution

It applies microcanonical inflection point analysis to finite-size models, identifying transition orders and discovering higher-order transitions, which broadens the understanding of phase transition universality.

Findings

Ising model exhibits second-order pseudo-phase transition

Baxter-Wu model exhibits first-order pseudo-phase transition

Both models show evidence of third-order transitions

Abstract

This article offers a detailed analysis of pseudo-phase transitions of Ising and Baxter-Wu models in two-dimensional finite-size lattices. We carry out Wang Landau sampling to obtain the density of states. Using microcanonical inflection point analysis with microcanonical entropy, we obtain the order of the psuedo-phase transitions in the models. The microcanonical analysis results of the second-order transition for the Ising model and the first-order transition for the Baxter-Wu model are consistent with the traditional canonical results. In addition, the third-order transitions are found in both models, implying the universality of higher-order phase transitions.