B Grade B
Infleqtion Cesium atom array: Logical qubits
12 logical qubits
As stated in the source: “12 logical qubits in a constant-depth logical CX ladder, [[4,2,2]] code”
Caveats
Distance-2 error detection with heavy post-selection: only 0.9% of encoded 12-logical-qubit shots survived post-processing. No absolute logical error rate per qubit is given in the abstract, only a relative improvement. Not peer-reviewed.
- Set-up
- Sqale QPU, 114 qubits. [[4,2,2]] error-detecting code (distance 2); constant-depth CX ladder on 12 logical qubits; encoded error rate more than 2x lower than unencoded (8-logical-qubit version nearly 4x lower). Post-processing survival rate 0.009 encoded vs 0.768 unencoded.
- Method
- Standard
- Compared only with
- results in the group “error detecting”
- Measured
- Not stated
- Published
- 16 September 2025
- Measured by
- Infleqtion (with University of Chicago and University of Wisconsin-Madison co-authors)
- Independent of the maker
- No
- Peer-reviewed
- No
- Repeated by others
- Not yet
Source
Demonstration of a Logical Architecture Uniting Motion and In-Place Entanglement, arXiv (preprint, v2 2 Apr 2026). Preprint. DOI: 10.48550/arXiv.2509.13247
Comparable results
| Machine | Value | Set-up | Published | Measured by | Grade | Record |
|---|---|---|---|---|---|---|
| Atom Computing Ytterbium atom array | 24 | error detecting | 18 Nov 2024 | Maker | B | r-000035 |
| QuEra Computing Harvard–MIT rubidium atom array | 48 | error detecting | 6 Dec 2023 | Maker | B | r-000033 |
History
- 27 October 2026: added
Spotted a mistake? Report an error, quoting r-000039.