B Grade B
Quantinuum Helios: Two-qubit gate fidelity
99.921% %
As stated in the source: “zone-averaged 2Q average infidelity 7.9(2) x 10^-4 (fidelity about 99.921%)”
Uncertainty: 99.919 to 99.923 (converted from the stated error and its uncertainty).
Caveats
Component-level figure averaged across the operation zones, not a full-system benchmark. Value is an infidelity as stated; the 99.921% fidelity is the arithmetic complement, not a separately quoted number in the fetched text. Converted from the stated average infidelity of 7.9(2)×10⁻⁴.
- Set-up
- Average over 8 qubit pairs in the 8 operation zones
- Method
- Clifford two-qubit randomized benchmarking (2QRB), leakage accounted for; cycle benchmarking also used
- Compared only with
- results in the group “mean”
- Measured
- Not stated
- Published
- 17 June 2026
- Measured by
- Quantinuum
- Independent of the maker
- No
- Peer-reviewed
- Yes
- Repeated by others
- Not yet
Source
A 98-qubit trapped-ion quantum computer with all-to-all connectivity, Nature (Springer Nature), vol. 655, pp. 81-86. Peer-reviewed paper. DOI: 10.1038/s41586-026-10676-4
Comparable results
| Machine | Value | Set-up | Published | Measured by | Grade | Record |
|---|---|---|---|---|---|---|
| Quantinuum H2 | 99.843% | mean | 2025 | Maker | B | r-000023 |
| Google Willow | 99.67% | mean | 9 Dec 2024 | Maker | B | r-000005 |
| Google Willow | 99.86% | mean | 9 Dec 2024 | Maker | B | r-000006 |
| QuEra Computing Harvard–MIT rubidium atom array | 99.54% | mean | 11 Oct 2023 | Maker | B | r-000032 |
History
- 27 October 2026: added
Spotted a mistake? Report an error, quoting r-000017.