Is demagnetization an efficient optimization method?

TL;DR

This paper compares demagnetization with the true ground state in the random field Ising model, concluding that demagnetization is not an effective optimization method due to persistent differences.

Contribution

It provides a detailed analysis showing that demagnetization does not reliably find the ground state in disordered systems, challenging its use as an optimization technique.

Findings

Demagnetized states differ significantly from ground states in the model.

Differences between states persist even in the thermodynamic limit.

AC demagnetization is not an efficient method for finding ground states.

Abstract

Demagnetization, commonly employed to study ferromagnets, has been proposed as the basis for an optimization tool, a method to find the ground state of a disordered system. Here we present a detailed comparison between the ground state and the demagnetized state in the random field Ising model, combing exact results in $d=1$ and numerical solutions in $d=3$. We show that there are important differences between the two states that persist in the thermodynamic limit and thus conclude that AC demagnetization is not an efficient optimization method.