Google cuts quantum errors 40-fold on its Willow chip, a step toward the machines that could one day threaten bitcoin's keys

Google says it has cleared one of the bottlenecks on the road to a useful quantum computer. In a blog post on Thursday, researchers Emma Rosenfeld and Craig Gidney of Google Quantum AI said the team had demonstrated "magic state cultivation" on its Willow chip. Magic states are special quantum states needed for the full range of quantum operations, and they are costly to produce and cannot be reused. The technique filters out flawed attempts with a series of error checks. Google reports about a 40-fold reduction in errors compared with states that were not cultivated, and a record logical fidelity of 99.99%. The team also moved the purified states between two kinds of error-correcting code. The results are published in the journal Science.

Why it matters for crypto: bitcoin's signatures rely on elliptic-curve cryptography that a large, error-corrected quantum computer could in theory break. In March, Google researchers estimated that this could take fewer than 500,000 physical qubits, about 20 times fewer than earlier estimates, The Block reported, and Google has set 2029 as the target for moving its own systems to post-quantum cryptography.

Google itself says larger demonstrations are still needed. No existing machine can attack bitcoin's keys, as Bitcoin.com News noted, but each step adds weight to calls this week from Coinbase and Starknet to start quantum-safe migrations now.