Quantum error correction below the surface code threshold
Rajeev Acharya, Dmitry A. Abanin, Laleh Aghababaie-Beni · Authored by Google Quantum AI and Collaborators (very large collaboration, ~300 authors); R. Acharya listed first.
Summary
Google Quantum AI demonstrated a superconducting surface-code memory whose logical error rate decreases as the code distance grows, crossing below the fault-tolerance threshold. Scaling from distance-3 to distance-5 to distance-7 codes, the logical qubit's error per cycle was suppressed by roughly a factor of two per increment, showing exponential error suppression. This provides experimental evidence that the surface code can reach the regime needed for scalable fault-tolerant quantum computing.
Key findings
- Achieved below-threshold operation: logical error rate falls as code distance increases
- Demonstrated ~2x error suppression (Lambda > 2) per increase in code distance up to distance-7
- Validated real-time decoding and long-lived logical memory beating the best physical qubit
Subjects & keywords
Cite this paper
Rajeev Acharya, Dmitry A. Abanin, & Laleh Aghababaie-Beni [Authored by Google Quantum AI and Collaborators (very large collaboration, ~300 authors); R. Acharya listed first.] (2025). Quantum error correction below the surface code threshold. Nature. https://doi.org/10.1038/s41586-024-08449-y
@article{acharya2025quantum,
author = {Rajeev Acharya and Dmitry A. Abanin and Laleh Aghababaie-Beni and {Authored by Google Quantum AI and Collaborators (very large collaboration, ~300 authors); R. Acharya listed first.}},
title = {Quantum error correction below the surface code threshold},
journal = {Nature},
year = {2025},
doi = {10.1038/s41586-024-08449-y},
url = {https://doi.org/10.1038/s41586-024-08449-y}
}