Google Quantum AI has announced a demonstration of “magic state cultivation” on its Willow quantum processor. The company says the work, published in Science, addresses a resource bottleneck involved in building error-corrected quantum computers.

Magic states are needed to perform a specific set of operations required for universal quantum computing. According to Google, producing high-quality, error-corrected magic states can consume a substantial share of a quantum computer’s capacity, and each state can be used only once.

The cultivation approach injects a noisy state into a small region of a quantum chip and uses coordinated measurements to identify and remove flawed attempts. Google says the process produced T-states with a logical fidelity of 99.99% and reduced errors by about 40 times compared with states that were not cultivated.

The company also described engineering challenges during development. It said electrical equipment drift and temperature variation affected an early benchmarking method, leading researchers to add system controls and develop a different technique that used cultivation to measure itself.

On Willow, Google says it also demonstrated transfers between color codes and surface codes, two quantum error-correction methods. The reported transfer moved states from a distance-3 color code to a distance-5 surface code.

Google said larger-scale demonstrations are still needed before the technique could support practical quantum computing, and that technical challenges remain.