B Grade B
Quantinuum H2: Logical error rate
1 × 10⁻⁵ error per circuit
As stated in the source: “0.001% logical error rate (vs 0.8% physical), about 800x lower”
Caveats
Relies on post-selection (error detection); about 30% of runs discarded. With pre-selection only, logical error rate was 0.17% (4.7x lower). Single-circuit error rate, not a per-cycle rate. Preprint; no journal reference listed on arXiv. This is an error per whole circuit with pre- and post-selection, not per correction cycle.
- Set-up
- Two pairs of logical qubits (4 logical qubits) entangled with the [[12,2,4]] code; pre-selection kept 15,483 of 22,000 runs, post-selection kept 15,409
- Method
- Carbon [[12,2,4]] CSS code, logical Bell-state preparation with pre- and post-selection
- Compared only with
- results in the group “carbon code bell postselected”
- Measured
- Not stated
- Published
- 2 April 2024
- Measured by
- Microsoft and Quantinuum (joint author team)
- Independent of the maker
- No
- Peer-reviewed
- No
- Repeated by others
- Not yet
Source
Demonstration of logical qubits and repeated error correction with better-than-physical error rates, arXiv. Preprint. DOI: 10.48550/arXiv.2404.02280
History
- 27 October 2026: added
Spotted a mistake? Report an error, quoting r-000024.