Will a Chinese team publish below-threshold surface-code error correction at code distance 9 or more before 31 December 2027?
deadline 2027-12-31
confidence medium
tier 4 evidence
35%PolySignal estimate
Resolution criterion
Yes if a peer-reviewed paper or an arXiv preprint from a Chinese institution reports a surface code of distance at least 9 with a measured error suppression factor above 1.
Verified starting state
In December 2025, the USTC team published a cover result in Physical Review Letters on Zuchongzhi 3.2 (107 qubits): below-threshold correction on a distance-7 surface code, suppression factor 1.4. Going from d=7 to d=9 requires roughly 161 data qubits plus ancillas. Google took about two years to go from d=5 to d=7.
What pushes it up
- USTC already achieved below‑threshold correction at distance 7, showing they have the expertise and hardware platform to attempt distance 9 (tier 1)
What pushes it down
- No announced roadmap or recent results for distance 9; scaling to d≥9 needs ~50 % more qubits and presents significant technical hurdles within the ~1.3 year window (tier 1)
What would move this number most
Whether the USTC team (or another Chinese group) can overcome the qubit‑count and error‑rate challenges in time to publish before the end of 2027.
How this number is built
| Deadline | 2027-12-31 |
| Base rate | 30% |
| Best evidence | tier 4 · 0 article(s) used |
| Independent runs | 35 · 35 (spread 0 pts) |
| Confidence | medium |
| Evidence cap | not triggered |
| Last revised | 2026-09-22 00:38 |
| Model | openai/gpt-oss-120b (Groq) |