Google shows 'magic state cultivation' works on its Willow chip

The bottleneck

Google Quantum AI says it has shown that "magic state cultivation" works in practice on its Willow processor, reducing errors about 40 times compared with not using it. ^[1] The result was published in Science on 15 October 2026. ^[1]

To run useful quantum programs you need to carry out certain operations and error-correct them. One way is to create "magic states", so called because they help produce operations that go beyond classical computing. ^[1] The catch is that high-quality, error-corrected magic states are very resource-heavy to make. Some estimates, Google says, suggest up to 95% of a quantum computer's capacity might be spent making them, leaving little for actual computing. They also cannot be reused once spent. ^[1]

How cultivation works

In 2024, Google researchers Craig Gidney, Noah Shutty and Cody Jones refined an idea from the literature into magic state cultivation. ^[1] It acts as a filter. A noisy state is injected into a small region of a chip, and coordinated measurements check for errors and discard flawed attempts, leaving an exceptionally pure state. ^[1]

On paper it looked promising, but making it work took many engineering steps. Google describes how research scientist Emma Rosenfeld saw data that seemed to defy physics, which turned out to come from a wrong assumption in the team's standard measurement technique. Noise from electrical equipment drift and temperature variation was interfering. The team added extra control and invented a new benchmarking method that uses cultivation to measure itself. ^[1]

The results

On Willow, Google reports a 40-fold reduction in errors relative to un-cultivated states and T-states with a record logical fidelity of 99.99%. ^[1] It describes this as the first demonstration of a practical solution to one of quantum computing's most severe resource bottlenecks. ^[1]

The team also took first steps in switching between two types of error-correcting code, grafting states from a distance-3 color code to a distance-5 surface code, and found the purified states survived the transfer. ^[1]

What it means

Google is clear about the limits: cultivation still has to be shown at a larger scale, and plenty of technical challenges remain. ^[1] This is a lab demonstration, not a product, and it does not mean useful quantum computers are about to arrive.

For business leaders, the practical message is about trajectory. If making magic states takes much less of a machine, the size of a quantum computer needed for practical tasks could shrink. ^[1] That would bring useful applications closer, although Google gives no timetable in its post.

It is also relevant to security planning. Quantum progress is the reason many organisations are reviewing their encryption. A single result like this does not change that picture on its own, but it is one more sign that the field is steadily solving engineering obstacles. Sensible organisations will keep tracking their plans for moving to quantum-resistant encryption rather than waiting for a dramatic announcement.

Source: Google — Bringing the magic: Google breaks open a bottleneck in quantum computing