QubitWire worked source-check example — checked 30 September 2026
Reader context: https://qubitwire.com/topics/error-correction
Primary paper: https://www.nature.com/articles/s41586-024-08449-y
Google Quantum AI and Collaborators. Published online 9 December 2024.
Correction: https://www.nature.com/articles/s41586-026-10559-8.pdf
Published 28 April 2026; Figure 3a repetition-code labels and legend keys amended.

Question: Does reduced logical-memory error prove an arbitrary useful fault-tolerant application?
Locate: “A surface code memory below threshold,” paragraph beginning “We characterize the logical performance,” and Figure 1c–d.
Answer: The Willow surface-code memory result shows logical error suppression as code distance increases under its measured conditions. The distance-7 neural-network-decoded runs span up to 250 correction cycles and average logical X and Z bases. Lower distances include multiple subgrids.
Boundary: It is a memory experiment. Application workloads, logical operations and full resource costs require separate evidence. The distance-5 real-time decoder and repetition-code study must not be substituted for the distance-7 memory conditions.
No source figure or body reproduced.
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