Quantum Simulation of Magnetic Materials: from Ab-Initio to NISQ

TL;DR

This paper demonstrates the simulation of magnetic excitations in 2D materials using cloud-based quantum computers, showing promising results despite current device limitations.

Contribution

It presents a method to simulate low-energy magnetic excitations of real materials starting from ab-initio calculations on NISQ devices via cloud platforms.

Findings

Simulated spin-wave spectra agree with classical benchmarks.

Achieved simulations with up to 48 qubits on a cloud platform.

Good scaling performance despite spectral feature challenges.

Abstract

Quantum computers are increasingly accessible, yet demonstrations of physically meaningful simulations for real materials remain scarce. In our work we simulate low-energy magnetic excitations, specifically spin-wave spectra, of chromium tri-halide monolayers. Starting from ab-initio electronic structure calculations for these two-dimensional magnets, we derive an effective spin model and simulate low-energy spin excitations using a real-time propagation of the spin system on the commercial quantum computing cloud platform IQM Resonance. The results for systems with up to 48 qubits are validated against classical benchmarks. While some spectral features remain challenging for today's NISQ devices, our simulation achieves good agreement at quasi-constant wall-time scaling, compared to the exponential scaling of classical methods. Our results demonstrate that, even in the absence of quantum advantage, useful quantum simulations of real materials are becoming possible for domain experts via commercial cloud access to quantum computers.