Chinese optical quantum computer Jiuzhang 2.0 can solve a problem 10^24 faster than a classical computer
Credit: CHAO-YANG LU/UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA Zuchongzhi
The first scientific breakthroughs in a field are often underwhelming: academically interesting, but of little practical value and widely disputed. So it proved when Google claimed to have turned the world of computing upside down.
A group of physicists at the company’s Santa Barbara laboratory said they had reached “quantum supremacy” in 2019 – the Eureka moment at which its experimental machine could outperform today’s most powerful supercomputers at a particular function.
It was controversial. Rivals such as IBM questioned the experiment’s validity as well as Google’s claim that traditional computers were unsuited to the task.
In December 2020, a group of Chinese researchers boasted of their own quantum moment. Scientists at the Hefei National Laboratory in eastern China were able to solve a physics problem known as boson sampling in just over three minutes, compared to the 2.5bn years that the country’s fastest supercomputer would take.
Unlike Google’s announcement, the discovery received little scientific pushback. Nor was it an isolated event. In recent months, Chinese researchers have unveiled a series of quantum computing and communication breakthroughs suggesting that the nation is not merely catching up, but leaping ahead of the West in key areas of the field. But is this cause for worry?
While academics have greeted China’s breakthroughs with enthusiasm, the US government has not.
Last month, the Hefei laboratory was added to a Commerce Department “entity list”, preventing American companies from doing business with it, alongside QuantumCTek – a separate entity associated with the lab’s lead researcher Jian Wei Pan.
The White House said they had been blacklisted for “acquiring and attempting to acquire US-origin items in support of military applications”. It placed five other Chinese companies on the list, in an attempt to slow down Beijing’s efforts to apply quantum computing for military purposes.
“China is not on a par with us in quantum,” says Jim Lewis, former US state department negotiator at the Washington-based Centre for Strategic and International Studies. “But they’re moving very quickly. And frankly, I think we underestimate the Chinese. They’re making a huge effort.”
Quantum computing relies on the intricacies of modern physics to carry out calculations that today’s machines find impossible. Instead of bits – the building blocks of computer code that are either in “0” or “1” – it relies on “qubits” that can also occupy the space between them. First proposed in the 1980s, usable versions are expected by the end of the decade.
About | What is quantum computing?
While the technology promises huge scientific leaps – modelling weather patterns, fighting climate change and researching cancer – it is also particularly suited to unscrambling encrypted communications and detecting submarines.
Last week, a report from Booz Allen Hamilton predicted China was unlikely to be able to decrypt data before 2030. However, it said spies were likely to start large-scale theft of encrypted data that could be stored in the hope it could one day be ready.
“Encrypted data with intelligence longevity, like biometric markers, covert intelligence officer and source identities, social security numbers and weapons’ designs, may be increasingly stolen under the expectation that they can eventually be decrypted,” it said.
The report recommended that companies start working on “post-quantum decryption”, an emerging field of protecting data in a way that quantum computers could not unlock.
“Intelligence agencies aren’t thinking, ‘How long do we have?’ They look at the sensitivity of data that we are encrypting today, and how long they want to keep it confidential,” says Ali El Kaafarani, the chief executive of PQShield, an Oxford University spin-out devoted to quantum cryptography. “What we know is that we are already at risk, and the risk is getting higher.”
PQShield employees have developed two of the seven algorithms being considered by the US National Institute of Standards and Technology as a standard for quantum encryption. The agency is due to make a decision by the end of the year.
Western intelligence agencies are also increasingly co-operating. The recently signed Aukus pact between the UK, US and Australia included pledges to share quantum information.
Quantum Computing | What are the applications?
Alan Woodward, a computer security expert at the University of Surrey who has advised GCHQ, says quantum encryption will largely offer protection but the prospect of China racing ahead in other fields of quantum research will also worry spooks.
“It hasn’t really reached the headlines so much, but it’s definitely one of those things in the background that people recognise as a strategic technology. We know it’s going to be important even if we can’t predict exactly how it’s going to be important.”
Despite the technology being far from ready for commercial use, the Government is seeking to protect British quantum companies. Woodward says this is partly an attempt to avoid a repeat of the Huawei debacle, in which ministers belatedly chose to rip the company out of its telecoms networks.
National security legislation coming into force in January will require security reviews of quantum technology companies if foreign investors seek to acquire a stake of more than 25pc.
“Unless we try and influence our future access to some of these technologies, then we could find we end up coming up with the bright ideas, but somebody else will effectively control it,” Woodward adds.
Boris Johnson wants Britain to become a world leader. “It is clear that we need to go big on quantum computing,” the Prime Minister said in a speech last month, outlining hopes for the UK to have 50pc of the global market.
China’s progress suggests that the target is exceedingly ambitious. But when it comes to national security, there may be little choice but to keep up.