Google’s new quantum computer chip Willow infinitely outpaces the world’s fastest supercomputers
Overview:
In a blog post on Monday, Google unveiled a new quantum computer chip called Willow, which demonstrates error correction and performance that paves the way to a useful, large-scale quantum computer. Willow has state-of-the-art performance across a number of metrics, enabling two major achievements.
- The first is that Willow can reduce errors exponentially as we scale up using more qubits. This cracks a key challenge in quantum error correction that the field has pursued for almost 30 years.
- Second, Willow performed a standard benchmark computation in under five minutes that would take one of today’s fastest supercomputers 10 septillion (that is, 1025) years — a number that vastly exceeds the age of the Universe.
Google’s quantum computer chip, Willow. Photo Credit…Google Quantum AI
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Quantum computing — the result of decades of research into a type of physics called quantum mechanics — is still an experimental technology. But Google’s achievement shows that scientists are steadily improving techniques that could allow quantum computing to live up to the enormous expectations that have surrounded this big idea for decades.
“When quantum computing was originally envisioned, many people — including many leaders in the field — felt that it would never be a practical thing,” said Mikhail Lukin, a professor of physics at Harvard and a co-founder of the quantum computing start-up QuEra. “What has happened over the last year shows that it is no longer science fiction.”
As a measure of Willow’s performance, Google used the random circuit sampling (RCS) benchmark. Pioneered by its team and now widely used as a standard in the field, RCS is the classically hardest benchmark that can be done on a quantum computer today. You can think of this as an entry point for quantum computing — it checks whether a quantum computer is doing something that couldn’t be done on a classical computer.
Random circuit sampling (RCS), while extremely challenging for classical computers, has yet to demonstrate practical commercial applications. Image Credit: Google AI.
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Willow’s performance on this benchmark is astonishing: It performed a computation in under five minutes that would take one of today’s fastest supercomputers 1025 or 10 septillion years. If you want to write it out, it’s 10,000,000,000,000,000,000,000,000 years. This mind-boggling number exceeds known timescales in physics and vastly exceeds the age of the universe. It lends credence to the notion that quantum computation occurs in many parallel universes, in line with the idea that we live in a multiverse, a prediction first made by David Deutsch.
Google’s assessment of how Willow outpaces one of the world’s most powerful classical supercomputers, Frontier, was based on conservative assumptions. For example, we assumed full access to secondary storage, i.e., hard drives, without any bandwidth overhead — a generous and unrealistic allowance for Frontier. Of course, as happened after we announced the first beyond-classical computation in 2019, we expect classical computers to keep improving on this benchmark, but the rapidly growing gap shows that quantum processors are peeling away at a double exponential rate and will continue to vastly outperform classical computers as we scale up.
In a research paper published on Monday in the science journal Nature, Google said its machine had surpassed the “error correction threshold,” a milestone that scientists have been working toward for decades. That means quantum computers are on a path to a moment, still well into the future, when they can overcome their mistakes and perform calculations that could accelerate the progress of drug discovery. They could also break the encryption that protects computers vital to national security.
“What we really want these machines to do is run applications that people really care about,” said John Preskill, a theoretical physicist at the California Institute of Technology who specializes in quantum computing. “Though it still might be decades away, we will eventually see the impact of quantum computing on our everyday lives.”
Sidebar –Quantum Computing Explained:
A traditional computer like a laptop or a smartphone stores numbers in semiconductor memories or registers and then manipulates those numbers, adding them, multiplying them and so on. It performs these calculations by processing “bits” of information. Each bit holds either a 1 or a 0. But a quantum computer defies common sense. It relies on the mind-bending ways that some objects behave at the subatomic level or when exposed to extreme cold, like the exotic metal that Google chills to nearly 460 degrees below zero inside its quantum computer.
Quantum bits, or “qubits,” behave very differently from normal bits. A single object can behave like two separate objects at the same time when it is either extremely small or extremely cold. By harnessing that behavior, scientists can build a qubit that holds a combination of 1 and 0. This means that two qubits can hold four values at once. And as the number of qubits grows, a quantum computer becomes exponentially more powerful. Google builds “superconducting qubits,” where certain metals are cooled to extremely low temperatures.
Many other tech giants, including Microsoft, Intel and IBM, are building similar quantum technology as the United States jockeys with China for supremacy in this increasingly important field. As the United States has pushed forward, primarily through corporate giants and start-up companies, the Chinese government has said it is pumping more than $15.2 billion into quantum research.
With its latest superconducting computer, Google has claimed “quantum supremacy,” meaning it has built a machine capable of tasks that are beyond what any traditional computer can do. But these tasks are esoteric. They involve generating random numbers that can’t necessarily be applied to practical applications, like drug discovery.
Google and its rivals are still working toward what scientists call “quantum advantage,” when a quantum computer can accelerate the progress of other fields like chemistry and artificial intelligence or perform tasks that businesses or consumers find useful. The problem is that quantum computers still make too many errors.
Scientists have spent nearly three decades developing techniques — which are mind-bending in their own right — for getting around this problem. Now, Google has shown that as it increases the number of qubits, it can exponentially reduce the number of errors through complex analysis.
Experts believe it is only a matter of time before a quantum computer reaches its vast potential. “People no longer doubt it will be done,” Dr. Lukin said. “The question now is: When?”
References:
https://blog.google/technology/research/google-willow-quantum-chip/
https://www.nytimes.com/2024/12/09/technology/google-quantum-computing.html