(BBC News) Google has unveiled a new chip that it claims takes five minutes to solve a problem that would currently take the world’s fastest supercomputers 10 septillion – or 10,000,000,000,000,000,000,000,000 – years to complete.
The chip is the latest development in a field known as quantum computing – which is attempting to use the principles of particle physics to create a new type of mind-blowingly powerful computer.
Google says its new quantum chip, dubbed “Willow”, incorporates key “breakthroughs” and “paves the way to a useful, large-scale quantum computer.”
However, experts say Willow is, for now, a largely experimental device, meaning a quantum computer powerful enough to solve a wide range of real-world problems is still years – and billions of dollars – away.
Quantum computers work in a fundamentally different way to the computer in your phone or laptop.
They harness quantum mechanics – the strange behaviour of ultra-tiny particles – to crack problems far faster than traditional computers.
It is hoped quantum computers might eventually be able to use that ability to vastly speed up complex processes, such as creating new medicines.
But there are fears it could be used for ill – for example, to break some types of encryption used to protect sensitive data.
In February, Apple announced that the encryption that protects iMessage chats is being made “quantum proof” to stop them being read by powerful future quantum computers.
Hartmut Neven, who leads Google’s Quantum AI lab that created Willow, describes himself as the project’s “chief optimist”.
He told the BBC that Willow would be used in some practical applications, but declined, for now, to provide more detail.
However, a chip able to perform commercial applications would not appear before the end of the decade, he said.
Initially, these applications would be the simulation of systems in which quantum effects are important.
“For example, relevant when it comes to the design of nuclear-fusion reactors to understand the functioning of drugs and pharmaceutical development, it would be relevant for developing better car batteries and another long list of such tasks.”
Neven says Willow’s performance meant it was the “best quantum processor built to date.”
Professor Alan Woodward, a computing expert at Surrey University, says quantum computers will be better at a range of tasks than current “classical” computers, but they will not replace them.
He warns against overstating the importance of Willow’s achievement in a single test.
“One has to be careful not to compare apples and oranges,” he told the BBC.
Google had chosen a problem to use as a benchmark of performance that was, “tailor-made for a quantum computer,” and this did not demonstrate “a universal speeding up when compared to classical computers.”
Nonetheless, he said Willow represented significant progress, in particular in what is known as error correction.
In simple terms, the more useful a quantum computer is, the more qubits it has.
However a major problem with the technology is that it is prone to errors – a tendency that has previously increased the more qubits a chip has.
But Google researchers say they have reversed this and managed to engineer and program the new chip so the error rate fell across the whole system as the number of qubits increased.
It was a major “breakthrough” that cracked a key challenge that the field had pursued “for almost 30 years,” Neven says.
He told the BBC it was comparable to “if you had an airplane with just one engine – that will work, but two engines are safer, four engines is yet safer.”
Errors are a significant obstacle in creating more powerful quantum computers, and the development was “encouraging for everyone striving to build a practical quantum computer,” Woodward says.
But Google itself notes that to develop practically useful quantum computers the error rate will still need to go much lower than that displayed by Willow.
Willow was made in Google’s new, purpose-built manufacturing plant in California.
Countries around the world are investing in quantum computing.
The UK recently launched the National Quantum Computing Centre (NQCC).
Its director, Michael Cuthbert, told the BBC he was wary of language that fuelled the “hype cycle” and says Willow was more a “milestone rather than a breakthrough.”
Nevertheless, it was “clearly a highly impressive piece of work.”
Eventually, quantum computers would help with a range of tasks including “logistics problems such as cargo freight distribution on aircraft, or routing of telecom signals, or stored energy throughout the national grid,” he says.
There were already 50 quantum businesses in the UK, attracting £800 million in funding and employing 1,300 people.
On Friday, researchers from Oxford University and Osaka University in Japan published a paper showcasing the very low error rate in a trapped-ion qubit.
Theirs is a different approach to making a quantum computer that is capable of working at room temperature – whereas Google’s chip has to be stored at ultra-low temperatures to be effective.
