Google proves magic state cultivation works on quantum hardware

Overview

Updated 1 hour ago

Google just cleared a major hurdle on the path to practical quantum computing. Its Willow processor purified the 'magic states' that enable universal computation with 40-fold fewer errors than conventional methods, in results published in Science.

Making magic states was expected to consume up to 95% of a future quantum computer's capacity. If the new cultivation protocol scales, fault-tolerant quantum machines become dramatically cheaper to build — a step toward cracking problems classical computers cannot touch.

Why it matters

Practical quantum computers may need millions of magic states. Cheaper production shrinks the machine needed, bringing useful quantum computing closer.

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Key Indicators

40x

Error reduction vs. un-cultivated states

Cultivation cut magic state preparation errors 40-fold on Willow.

99.99%

Logical fidelity of cultivated T-states

Record fidelity for error-corrected magic states.

Pass rate for cultivation checks

Only about 8% of initial attempts passed every fidelity check.

54 of 105

Qubits used on Willow

The experiment used at most 54 of Willow's 105 qubits.

95%

Capacity magic states were expected to consume

Estimates said up to 95% of a quantum computer's capacity could go to magic state production.

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Craig Gidney

Google Quantum AI research scientist

Co-authored the 2024 theory paper proposing magic state cultivation

Emma Rosenfeld

Google Quantum AI research scientist

Ran the cultivation experiment on Willow

Noah Shutty

Google Quantum AI research scientist

Co-developed magic state cultivation theory

Cody Jones

Google Quantum AI research scientist

Co-developed magic state cultivation theory

Organizations Involved

Google Quantum AI

Quantum computing research division of Google

Lead organization in the cultivation demonstration

Google's quantum computing research arm, developer of the Willow processor.

Timeline

2024 October 2026

4 events Latest: 2 days ago

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October 2026
Google demonstrates cultivation on Willow, publishes in Science
Latest Research

Experimental results show 40x error reduction and 99.99% fidelity for cultivated magic states. About 8% of attempts pass checks.
2 days ago
Crypto observers weigh quantum threat implications
Analysis

Analysts note the result advances engineering that could eventually threaten RSA and Bitcoin, though scaling challenges remain substantial.
2 days ago
2025
Gidney estimates RSA-2048 factoring with under a million qubits
Analysis

Gidney's analysis suggests cultivation could enable RSA-2048 breaking with under a million noisy qubits, a 20-fold drop from earlier estimates.
2025
2024
Theory paper proposes magic state cultivation
Research

Gidney, Shutty, and Jones publish the cultivation protocol, promising large reductions in magic state production cost.
2024

Scenarios

Google scales cultivation to practical code sizes

Possible Resolves by End of 2027

Discussed by: Google Quantum AI researchers, whose projections suggest halving Willow's hardware noise would push errors to about 2 in 100,000

Google's next step is running cultivation at a larger scale, moving states into codes of roughly 500 qubits. If the technique holds at distance-5 or larger surface codes, practical fault-tolerant machines come significantly closer. The team has already shown states can be grafted from a distance-3 color code to a distance-5 surface code.

Cultivation hits a scaling wall

Unlikely Resolves by Q2 2027

Discussed by: Researchers noting the 8% pass rate and error mechanisms that simulations suggest could appear at very low noise levels

The current filter keeps only about 8% of attempts, and the largest demonstration used just 54 of Willow's 105 qubits. Moving states into a roughly 500-qubit code does not fit on today's chip. New error mechanisms could emerge as noise drops below current levels, making the projected error reductions harder to achieve than the model predicts.

Rival quantum labs replicate cultivation on other hardware

Possible Resolves by Q2 2028

Discussed by: Industry observers and competing quantum computing teams at IBM, PsiQuantum, and others

Cultivation is theory-agnostic about hardware, but each platform has different noise characteristics. If another lab demonstrates the technique on its own chip, it validates the method broadly and accelerates the field. IBM's superconducting processors and PsiQuantum's photonic approach are the most likely candidates.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

2023

Google breaks quantum error correction threshold (2023)

Google's Sycamore processor, later upgraded to Willow, showed that adding more qubits reduced errors — crossing the error correction threshold for the first time. The result, published in Nature, proved quantum error correction could work on real hardware.

Then

Established that error correction is feasible on superconducting processors, not just in theory.

Now

Became the foundation for Willow's performance and directly enabled the magic state cultivation result in 2026.

Why this matters now

Same lab, same hardware line, same pattern: theoretical breakthrough, hardware demonstration, then scaling. The below-threshold result was the previous bottleneck Google broke.

1947-1960s

Transistor replaces vacuum tubes (1950s)

The transistor, invented at Bell Labs in 1947, replaced bulky, hot, unreliable vacuum tubes. Each tube cost money, consumed power, and failed often. The transistor made amplification dramatically cheaper and more reliable.

Then

Electronics shrank and became affordable, enabling commercial computers, radios, and televisions.

Now

The cost reduction unlocked entire industries. Computing went from room-sized machines to handheld devices.

Why this matters now

Magic states are the quantum equivalent of vacuum tubes — expensive, scarce, and essential. Google's cultivation method is a cost breakthrough that could unlock practical quantum computing the way transistors unlocked modern electronics.