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Willow represents Google’s latest development in its goal to produce quantum computing that can scale beyond error limits
Researchers from Google have demonstrated a new generation of quantum computer, called Willow, which is able to run its random circuit sampling (RCS) benchmark significantly faster than a supercomputer.
Willow represents a significant step forward in the development of quantum computers and how they handle noise, which affects performance. However, the tech giant hopes the technology will evolve to a stage where it can surpass supercomputing performance in real-world applications, not just benchmarks.
In a Twitter post, CEO Sundar Pichai described Willow as a new state-of-the-art quantum computing chip, which he claimed can reduce errors exponentially. “In benchmark tests, Willow solved a standard computation in less than five minutes,” he said. On a leading supercomputer, Pindar claimed the same problem would take more than 1,025 years to solve, which is far beyond the age of the universe.
“We see Willow as an important step in our journey to build a useful quantum computer with practical applications in areas like drug discovery, fusion energy, battery design and more,” he added.
In a blog post discussing the finding of research published in Nature, Hartmut Neven, founder and lead of Google Quantum, said that Google researchers have demonstrated that Willow’s error rate decreases as the number of qubits increases.
“The more qubits we use in Willow, the more we reduce errors, and the more quantum the system becomes. We tested ever-larger arrays of physical qubits, scaling up from a grid of 3×3 encoded qubits, to a grid of 5×5, to a grid of 7×7 — and each time, using our latest advances in quantum error correction, we were able to cut the error rate in half. In other words, we achieved an exponential reduction in the error rate,” he wrote in the blog.
Neven said that Willow is one of the first examples of real-time error correction on a superconducting quantum computer system. This is an important step in getting to where quantum computers can be used to do useful things. “If you can’t correct errors fast enough, they ruin your computation before it’s done,” Neven said.
Neven described the work the research team at Google had done as a “beyond breakeven” demonstration: “Our arrays of qubits have longer lifetimes than the individual physical qubits do, an unfakable [sic] sign that error correction is improving the system overall.”
Neven claimed Willow is “the most convincing prototype for a scalable logical qubit built to date”, adding that it brings the technology closer to where quantum computing technology will eventually be able to run practical, commercially relevant algorithms, which cannot be replicated on conventional computers.
While Neven admits the benchmark Google used is not relevant to real-world applications, the goal of the research team is to step into the realm of algorithms that are beyond the reach of classical computers and that are useful for real-world, commercially relevant problems.
“We’ve done scientifically interesting simulations of quantum systems, which have led to new scientific discoveries but are still within the reach of classical computers,” he said.
