Google Quantum AI has experimentally demonstrated “magic state cultivation” on a superconducting quantum processor, according to a paper published in Science on Oct. 15. In a public announcement, Google CEO Sundar Pichai said the work ran on the company’s Willow processor and marked the first demonstration of the technique on physical hardware.
Fault-tolerant quantum computers need a universal set of logical operations. The paper explains that non-Clifford gates, which are required for universal computation, remain costly in many error-correction architectures. Magic states are specially prepared quantum states that enable those operations. Cultivation is designed as a more efficient alternative to resource-heavy magic-state distillation.
In the experiment, the team implemented cultivation with code-switching into a surface code and developed a fault-tolerant measurement protocol to bound the resulting state’s fidelity. The paper reports that cultivation cut the error rate by a factor of 40 and reached a state fidelity of at least 0.9999(1), while retaining 8% of attempts.
The researchers describe the experiment as evidence that cultivation can address a major obstacle in quantum computing. Pichai framed it more cautiously as another step toward useful, error-corrected quantum computers, rather than a claim that such machines are already practical.
