Overview
- Google published the result in Science on Oct. 15 showing an experimental implementation of magic‑state cultivation on its Willow superconducting processor.
- The team reported about a 40‑fold reduction in preparation errors and recorded T‑state logical fidelity of 99.99% for states that passed its checks.
- The protocol kept only about 8% of preparation attempts, used up to 54 of Willow’s 105 physical qubits, and moved cultivated states from a distance‑3 color code into a distance‑5 surface code.
- Researchers fixed measurement errors caused by electrical drift and temperature fluctuations, added hardware controls, and developed a self‑referential benchmarking method to validate the very low error rates.
- The result is an important experimental milestone but remains small scale; cultivation must be scaled and independently verified before it can materially reduce machine sizes or change timelines for cryptographic risk.