safety security
Fault Tolerance Protected the Qubit, Not the Telemetry
A 156-qubit processor’s execution record identified a distance-one logical input with total variation of at least 0.927.
Summary
A 156-qubit processor’s execution record identified a distance-one logical input with total variation of at least 0.927.
Quantum error-correction hardware emits syndrome, decoder, reset and timing records separately from its logical answer. The paper proves exponentially small logical-input leakage only under explicit locality, correctability and convergence assumptions, with each logical axis paying its own code distance. On a 156-qubit superconducting processor, the sufficient certificate missed by a factor of 21.5 and could not be invoked. Directly measured records from a distance-one memory identified the input with total variation of at least 0.927; randomized encoding returned the statistic to the floor without extra two-qubit gates. The result warns that fault tolerance does not automatically make operational telemetry private.
Why it matters
A 156-qubit processor’s execution record identified a distance-one logical input with total variation of at least 0.927.
Limits and context
- The paper proves exponentially small logical-input leakage only under explicit locality, correctability and convergence assumptions, with each logical axis paying its own code distance.
- On a 156-qubit superconducting processor, the sufficient certificate missed by a factor of 21.5 and could not be invoked.
- The result warns that fault tolerance does not automatically make operational telemetry private.
Key claims
A 156-qubit processor’s execution record identified a distance-one logical input with total variation of at least 0.927.
Qualification: The paper proves exponentially small logical-input leakage only under explicit locality, correctability and convergence assumptions, with each logical axis paying its own code distance.
Evidence: source-2026-09-10-013
Sources
- arXiv preprint 2609.09334arXiv · primary research
Corrections
No corrections have been recorded for this story.