Google has announced its latest quantum processor, dubbed Willow. In a blog post, the tech giant claims this state-of-the-art chip stands apart from competitors due to two major achievements: its incredible speed in computation benchmarks, and the way it reduces errors exponentially as qubits are scaled up.
As per our headline, Willow is a benchmarking beast. Google tested the chip in the random circuit sampling (RCS) benchmark, which is claimed to be "the classically hardest benchmark that can be done on a quantum computer today." It flew through the calculation and completed it in under five minutes. By way of contrast, one of the leading Supercomputers in 2024, Frontier, would take 1025 or 10 septillion years to finish the same calculation, according to Google. That's 10,000,000,000,000,000,000,000,000 years, which exceeds the age of the known universe. Of course, running anything for that length of time would be impossible in practice. Our sun is estimated to only have another five billion years of life left, for example.
Google was also being generous with its estimates, with regard to Frontier, assuming full access to secondary storage as needed, without any bandwidth overhead.
Another major leap forward claimed for Willow is how it can reduce errors exponentially as it scales up to include more qubits. According to Google this advance "cracks a key challenge in quantum error correction that the field has pursued for almost 30 years." Google backs up its claims with a heavyweight research paper dubbed Quantum error correction below the surface code threshold and published for all to peruse.
In tests, Google used increasingly large arrays of qubits, scaling from a grid of 3x3 encoded qubits to a grid of 5x5, to a grid of 7x7. Each time it saw the error rate cut in half.
Willow and Google's next steps
Google says it fabricated Willow at its purpose-built state-of-the-art facility in Santa Barbara. Willow features 105 qubits, which may not sound like a big deal, but the company insists that it is "focusing on quality, not just quantity — because just producing larger numbers of qubits doesn’t help if they’re not high enough quality."
In the official blog, Willow is also compared to previous-generation Quantum chips from Google. For example, Willow is claimed to retain qubit excitation (T1) levels 5x longer than previous chips.
Google will continue to work with Willow to advance its quantum roadmap. Next up, Google hopes that it can "step into the realm of algorithms that are beyond the reach of classical computers and that are useful for real-world, commercially relevant problems." Only once these two goals can dovetail will we start to see the first promises of quantum computing delivered.
The Willow chips have come into view about five years since Google boldly claimed “quantum supremacy” with its 54-qubit Sycamore quantum processor. However, Sycamore proved to be quite controversial as IBM very publicly disputed Google's claims.
