Ground states and thermal states of the random field Ising model

TL;DR

This paper investigates the ground and thermal states of the random field Ising model, revealing how disorder influences phase transitions and thermodynamic properties through numerical simulations.

Contribution

It provides a comprehensive numerical analysis of ground and thermal states, highlighting the correlation near the critical line and the behavior of thermodynamic peaks under disorder.

Findings

Sharp peaks in specific heat and susceptibility near critical points

Strong correlation between ground and thermal states near the critical line

Large domains flipping cause sharp thermodynamic peaks

Abstract

The random field Ising model is studied numerically at both zero and positive temperature. Ground states are mapped out in a region of random and external field strength. Thermal states and thermodynamic properties are obtained for all temperatures using the the Wang-Landau algorithm. The specific heat and susceptibility typically display sharp peaks in the critical region for large systems and strong disorder. These sharp peaks result from large domains flipping. For a given realization of disorder, ground states and thermal states near the critical line are found to be strongly correlated--a concrete manifestation of the zero temperature fixed point scenario.