Quantinuum’s Helios-1 processor recorded a logical two-qubit gate error rate at code distance 5, extending the company’s error-correction work from protected memory to operations on encoded quantum information.
Researchers tested triangular color codes on the trapped-ion system at distances 3, 5 and 7. The paper reports logical two-qubit Clifford gate tests at distances 3 and 5, with an estimated distance-5 error rate of (7 +3/−3) × 10⁻⁵ per logical gate. That figure measures gate performance, separate from the per-cycle rate used for the paper’s memory experiment.
Code distance describes the level of protection built into an encoded logical qubit. A greater distance requires more resources, and the circuits needed for a distance-7 gate test exceeded Helios-1’s available qubit capacity, the paper says. Researchers therefore did not report a distance-7 gate measurement.
The study also measured memory performance across the three code distances. Memory tests track how well encoded information is retained through correction cycles; gate tests measure operations on that information.
The findings cover quantum memory and selected gate operations. The study does not demonstrate a complete universal fault-tolerant quantum computer. Quantinuum says it plans to make Apollo, its planned universal fault-tolerant system, available by 2029. The paper identifies below-threshold scaling for high-fidelity color-code magic-state preparation and a full Clifford-plus-T circuit using real-time decoding as work that remains.
