In the great expanse of nature, systems evolve to adapt and overcome obstacles. This approach is mirrored by quantum computing, which uses the mechanics of the universe to solve problems that were previously thought to be insurmountable. Google Quantum AI has adopted this mindset, pushing the limits of science to build disruptive technology. Willow, the newest and most powerful superconducting quantum computer chip, is the most recent milestone in this quest.
The Journey to Willow
Google Quantum AI’s quest to create quantum computers capable of solving previously unsolvable problems began in 2017 with the Foxtail chip. This was followed by Bristlecone in 2018 and the revolutionary Sycamore chip in 2019, which set a new record as the first quantum computer to exceed the top classical supercomputer on a computational task: random circuit sampling.
Sycamore proved scalability with its first logical qubit, a significant milestone. However, quantum coherence periods, or the time it takes for qubits to maintain their intended state, remained a limiting constraint. Willow addresses this issue by raising coherence times from 20 microseconds in Sycamore to an astonishing 100 microseconds—a fivefold improvement.
A Leap Forward in Quantum Performance
Willow’s breakthroughs are the outcome of Google’s specialized superconducting quantum chip fabrication facility in Santa Barbara. This cutting-edge facility has already enabled advancements that exceed Sycamore’s achievements. Willow’s logical qubits are now operating below the critical quantum error correction threshold, a goal targeted by researchers since the 1990s.
The capacity to reduce errors exponentially is a breakthrough accomplishment. With each addition of physical qubits and scaling of surface codes from 3 to 5 to 7, error rates are cut in half. This assures that logical qubits have longer lives, even as they scale, while also enhancing accuracy through quantum error correction.
A New Era of Speed and Efficiency
The performance benchmarks highlight Willow’s strengths. In a head-to-head test against one of the world’s most powerful supercomputers, Willow completed a random circuit sampling computation in under five minutes. A conventional supercomputer would need around 10²⁵ years to complete the same operation, which is much longer than the universe’s lifetime.
This finding emphasizes the fast expanding gap between classical and quantum computers for some applications. Willow opens up new possibilities in drugs, batteries, and fusion power, solving previously thought-to-be insurmountable obstacles.
What Makes Willow Special?
Willow is the result of years of effort in quantum hardware design. Its configurable qubits and couplers enable:
Superfast gates and operations: Low mistake rates.
Reconfigurability: It is the process of optimizing hardware in-place to support a variety of applications.
High connectivity: Effectively expresses complex algorithms.
This tunability ensures consistent high performance across the gadget. Outlier qubits with greater error rates can be modified to match the rest of the system, resulting in consistent performance. Furthermore, software-driven calibration procedures are constantly used to minimize errors across all qubits.
Willow by the Numbers
Here’s a breakdown of the technical specifications:
- Number of qubits: Large and scalable.
- Connectivity: High, with robust interactions between qubits.
- Error probabilities: Low across single and two-qubit gates and measurements.
- Coherence time: Increased to 100 microseconds.
- Measurement rate: Exceptional, enabling faster computations.
- Application performance: Benchmarking far beyond classical capabilities.
Looking Ahead
Willow is an important step in developing large-scale, error-corrected quantum computers. This advancement positions quantum computing to enable economically feasible applications that could transform areas such as healthcare, energy, and materials science. Willow gives a glimpse into the future of quantum computing, demonstrating its limitless possibilities.
By drawing inspiration from nature’s ability to develop and adapt, Google Quantum AI continues to push the frontiers of what is possible. Willow is another significant step toward solving the unsolvable and exploring the tremendous possibilities of quantum computing, ushering forth a new era of creativity and discovery.
