# Magnetic hysteresis experiments performed on quantum annealers

## TL;DR

Researchers developed a method to study magnetic hysteresis on quantum computers, observing unexpected behaviors in spin systems.

## Contribution

First protocol to experiment on magnetic hysteresis using programmable quantum annealers.

## Key findings

- Hysteresis loops showed nonmonotonic dependence on quantum fluctuations.
- Disorder-induced steps and nonmonotonicities were observed in the hysteresis behavior.
- Quantum annealers demonstrated potential for studying nonequilibrium magnetic phenomena.

## Abstract

While quantum annealers have emerged as versatile and controllable platforms for experimenting on correlated spin systems, the important phenomenology of magnetic memory and hysteresis remain unexplored on hardware designed to escape metastable states via quantum tunneling. Here, we present the first general protocol to experiment on magnetic hysteresis on programmable quantum annealers and implement it on three D-Wave superconducting qubit quantum annealers, using up to thousands of spins, for both ferromagnetic and disordered Ising models, and across different graph topologies. We observe hysteresis loops whose area depends nonmonotonically on quantum fluctuations, exhibiting both expected and unexpected features, such as disorder-induced steps and nonmonotonicities. Our work establishes quantum annealers as a platform for probing nonequilibrium emergent magnetic phenomena, thereby broadening the role of analog quantum computers into foundational questions in condensed matter physics.

A programmable magnetic hysteresis experiment protocol on analog quantum computers is introduced.