Curator's Take
AI Commentary
This article provides the first systematic, cloud‑based comparison of how well today’s superconducting and trapped‑ion processors can generate large GHZ states, a key resource for many quantum algorithms and error‑correction schemes. By measuring raw fidelities without mitigation, it shows that even on machines boasting dozens of physical qubits, usable multipartite entanglement often tops out at only a few dozen—while a 12‑qubit ion trap can reliably harness its full register, underscoring the current strength of connectivity and coherence in trapped‑ion platforms. The results give developers a realistic yardstick for choosing cloud providers and highlight where hardware and compilation improvements are most needed to close the gap between qubit count and functional quantum volume.
— Mark Eatherly
Summary
Quantum computing has rapidly evolved into a diverse ecosystem of hardware platforms that differ in their underlying technologies and operational characteristics. Consequently, benchmarking has become essential for identifying the strengths of quantum processors, comparing their performance, and enabling informed decisions when selecting the most appropriate quantum computing platform for specific applications. In this work, we benchmark nine commercially accessible quantum processors from five vendors, spanning superconducting and trapped-ion technologies, using the multipartite entanglement benchmark from the QuSquare suite. All experiments were performed through remote cloud-access services, with the default compilation of each provider and without error mitigation, reflecting the performance experienced by end users. The benchmark estimates the fidelity of Greenberger--Horne--Zeilinger (GHZ) states by direct fidelity estimation and searches for the largest GHZ state whose fidelity is compatible, within the statistical error, with the genuine multipartite entanglement (GME) threshold $F=1/2$. Our results reveal a substantial gap between the total number of physical qubits available on a processor and the size of the largest GHZ state passing the benchmark: the best superconducting processors reach $N^*=27$ and $N^*=24$ qubits, less than a quarter of their registers, whereas the 12-qubit trapped-ion processor passes with its full register. We further show that median calibration data are poor predictors of the benchmark outcome, and that the reported sizes depend strongly on the statistical decision rule: requiring certified GME reduces the number of devices that succeed at any tested size from nine to four. These results provide a baseline for future cross-platform benchmarking of quantum processors.