Extreme Quantum Advantage when Simulating Strongly Coupled Classical Systems

TL;DR

This paper demonstrates that quantum simulators can efficiently model strongly coupled classical spin systems, with the quantum advantage increasing with interaction range and temperature, surpassing classical memory requirements.

Contribution

It reveals that quantum simulators provide unbounded memory advantages over classical models for strongly coupled spin systems as interaction length and temperature grow.

Findings

Quantum advantage scales with interaction range and temperature.

Quantum simulators require less memory than classical models.

Advantage grows without bound as interaction increases.

Abstract

Classical stochastic processes can be generated by quantum simulators instead of the more standard classical ones, such as hidden Markov models. One reason for using quantum simulators is that they generally require less memory than their classical counterparts. Here, we examine this quantum advantage for strongly coupled spin systems---the Dyson-like one-dimensional Ising spin chain with variable interaction length. We find that the advantage scales with both interaction range and temperature, growing without bound as interaction increases. Thus, quantum systems can very efficiently simulate strongly coupled classical systems.