Large-Scale Quantum Circuit Simulation on an Exascale System for QPU Benchmarking

TL;DR

This paper benchmarks a 98-qubit quantum processor using large-scale classical simulations on an exascale supercomputer to identify the noise-tolerance threshold and validate quantum outputs.

Contribution

It demonstrates the use of exascale classical simulation to validate quantum processors and establishes a quantitative noise boundary up to 93 qubits.

Findings

Helios-1 remains noise-tolerant up to 48 qubits.

Classical simulation validates quantum outputs up to 93 qubits.

Beyond 95 qubits, outputs are statistically indistinguishable from random sampling.

Abstract

Recent advances in quantum computing have enabled the development of quantum processors with hundreds of qubits. However, noise continues to limit the amount of useful information that can be extracted from these systems, making it essential to identify the regime in which experimental outputs remain reliable. In this work, we benchmark Quantinuum Helios-1, a 98-qubit trapped-ion quantum processing unit, using the linear ramp quantum approximate optimization algorithm (LR-QAOA). To this end, we perform large-scale noiseless simulations on JUPITER, Europe's first exascale supercomputer, for circuits of up to 48 qubits and 3,384 two-qubit gates. These simulations, executed on 4,096 nodes equipped with 16,384 GH200 superchips and high-bandwidth CPU-GPU interconnects, provide a reference for validating experimental results at the edge of classical tractability. We find that, up to 48 qubits, Helios-1 remains in a noise-tolerant region, i.e., its samples cannot be clearly distinguished from those coming from a noiseless simulation. We then extend the analysis to larger system sizes using experimental data only, and apply a mean-of-means resampling procedure with a 3$\sigma$ threshold to determine whether the QPU output is statistically distinguishable from random sampling. This analysis identifies a regime of coherent performance up to 93 qubits (12,834 two-qubit gates), beyond which, at 95 qubits, the outputs become statistically indistinguishable from random sampling. These results demonstrate how exascale classical simulation can be used to validate quantum processors, and provide a quantitative boundary between noise-tolerant and random regimes in quantum processors.