A Google Quantum AI experiment now published in Science reduces magic-state error fortyfold, reporting fidelity of at least about 99.99%. Magic states supply operations needed for universal quantum computation that ordinary error-correcting machinery cannot cheaply provide. The experiment refines them inside a protected logical qubit, then demonstrates transfer into a surface-code arrangement.
The number to keep beside the fidelity is 8%: that is the share of attempts retained through the checks used to measure it. Better output quality and production yield belong together. This is October peer-reviewed publication of work already available as a December 2025 preprint; it is not a claim that the experiment happened this week. Authors’ October 15 announcement · Research abstract · Paper and version history