Hysteresis and avalanches in the T=0 random-field Ising model with 2-spin-flip dynamics

TL;DR

This study compares 2-spin-flip and 1-spin-flip dynamics in the 3D Gaussian random-field Ising model at T=0, revealing that the universality class of the disorder-induced phase transition remains unchanged despite differences in coercivity and avalanche distributions.

Contribution

It introduces and analyzes the effects of 2-spin-flip dynamics on the non-equilibrium behavior of the model, showing universality class invariance.

Findings

2-spin-flip dynamics suppress coercivity

Avalanche size distribution remains similar

Universality class unchanged by dynamics change

Abstract

We study the non-equilibrium behavior of the three-dimensional Gaussian random-field Ising model at T=0 in the presence of a uniform external field using a 2-spin-flip dynamics. The deterministic, history-dependent evolution of the system is compared with the one obtained with the standard 1-spin-flip dynamics used in previous studies of the model. The change in the dynamics yields a significant suppression of coercivity, but the distribution of avalanches (in number and size) stays remarkably similar, except for the largest ones that are responsible for the jump in the saturation magnetization curve at low disorder in the thermodynamic limit. By performing a finite-size scaling study, we find strong evidence that the change in the dynamics does not modify the universality class of the disorder-induced phase transition.