Helios colour-code experiment reduces logical-memory errors

What happened

Quantinuum’s 19 October paper reports a logical-memory error rate of about five errors per million correction cycles at code distance seven. Increasing the code distance from three to five to seven reduced memory errors by a fitted factor of about twelve at each step. The experiment decoded its results offline; streaming decoder processing was benchmarked separately. Memory cycles, logical gates and a complete computer are different measurements.