Google tests a quantum error-correction method on Willow and reduces errors by about 40 times, with peer-reviewed results

A study published in Science reports that Google's Willow processor reduced errors in special quantum states, called magic states, by about 40 times compared with states that had not gone through the process. The team also produced T-states with 99.99% logical fidelity, meaning very high accuracy. The experiment combined two types of error-correction codes. Google says producing magic states could use up to 95% of a quantum computer's capacity and acknowledges that the method still needs to work at larger scale.

Google's results come from experiments on real quantum hardware. By comparison, IonQ's claim of a 74-times speed improvement using qLDPC codes on Oct. 6 was based on comparisons between two code designs and a method that measures errors step by step. IonQ's blog does not describe a hardware experiment.

Results tested on real hardware and published in a peer-reviewed journal carry more weight than claims based only on theoretical comparisons. Google has provided that evidence, while also acknowledging the next challenge: proving the method works at larger scale.

Google. (2026, October 15). Research on magic-state cultivation using the Willow quantum processor. Google Blog