Google achieves practical solution to quantum computing hurdle on Willow chip

Google demonstrated a practical solution to a major quantum computing hurdle by cutting errors about 40-fold on its Willow chip, reaching a record 99.99% fidelity in research published in Science on October 15. This method, called magic state cultivation, efficiently creates crucial magic states, which were previously estimated to consume up to 95% of a machine’s capacity. Google estimates this method could substantially shrink the machine size needed for practical tasks, potentially reducing the qubit requirement for a quantum attack on Bitcoin from fewer than 500,000 to smaller scales, as demonstrated in a 2025 estimate by Craig Gidney for breaking RSA. Currently, Willow has 105 qubits, far below the required threshold, and Google noted that larger-scale demonstration is still needed.