China Seeks a Quantum Leap in Computing

The advance follows similar ones made in recent years by

International Business Machines Corp.

,

Alphabet Inc.’s

Google and other companies in the U.S., which is widely viewed as the world leader in quantum computing research.

Baidu said its new computer—an assemblage of metal plates and wires that looks a bit like an oversize chandelier—is accessible free of charge via a website and mobile app to researchers, engineers and even schoolchildren. U.S. companies, including IBM and Google, also offer websites to access their quantum computers.

“It will act as a base for people to learn more about the technology,” Yvonne Gao, an assistant professor at the National University of Singapore’s Centre for Quantum Technologies, says of Qian Shi, the name of the new computer, which means “heaven is the origin of everything” in Mandarin Chinese. “It’s definitely useful for boosting innovation in this direction.”

Whether quantum-computing devices will eventually move from the lab to widespread commercial use remains a debate in the science community. But mathematical proofs indicate that fully realized quantum computers would be able to solve in seconds certain problems that would take even the fastest supercomputers thousands or millions of years.

Quantum computers derive their extraordinary speed from their use of so-called quantum bits, or qubits, instead of the digital zeros and ones used to represent data in conventional computers.

Bits, as those zeros and ones are known, can only have a single value. But qubits—which are encoded into subatomic and atomic particles including electrons, photons and ions—can exist as a zero and a one at the same time. This phenomenon, known as superposition, makes qubits superbly efficient at handling certain calculations, such as those required to simulate the physical world or optimize business processes.

Qubits are also special for their ability to enter quantum entanglement, meaning two particles, at a distance, will mirror each other’s behaviors as though they are linked. Such a feature can be exploited to coordinate computation. On Wednesday three physicists who confirmed the existence of this phenomenon received the Nobel Prize in Physics.

Figuring out how to control these properties has proven to be a great challenge. Programming qubits into the right states requires a setup that allows interacting with them. But keeping them in those states long enough to perform computations requires just the opposite: completely isolating them from other particles that could make the qubits lose their encoded information.

“That’s the great engineering paradox,” says Steven Girvin, a professor of physics at Yale University.

If researchers succeed, quantum computers might make it possible for battery makers to predict complex chemical reactions to design higher-performing devices. Similarly, the computers might speed the development of new medicines by helping drugmakers simulate protein folding, the intricate process by which these large biological molecules assume their shape.

Quantum computers might also be capable of defeating the standard form of encryption used to secure communications worldwide—a matter of great concern to financial institutions as well as governments anxious to keep intelligence and military secrets.

Quantum physicists say it’s this worrisome possibility—and the fear of being left behind—that has fueled massive government interest and investment into the technology globally.

A traditional computer tries

each combination individually.

A quantum computer tries

all combinations at once.

A traditional computer tries

each combination individually.

A quantum computer tries

all combinations at once.

A traditional computer tries

each combination individually.

A quantum computer tries

all combinations at once.

A traditional computer tries

each combination individually.

A quantum computer tries

all combinations at once.

A traditional computer tries

each combination individually.

A quantum computer tries

all combinations at once.

The U.S., Germany, France and India are among the countries that have each committed upward of $1 billion in state funding to be spent on quantum technologies research over the next few years. Beijing doesn’t release numbers on its planned investments, but Chinese media reports and U.S. policy research groups, including Santa Monica, Calif.-based think tank Rand Corp. and McKinsey, have placed its commitment over a similar period to between $1 billion and more than $15 billion.

Compared with the U.S., China was a latecomer to quantum computing. It sought first to dominate a related field known as quantum communication, which aims to develop a method of encryption that’s nearly impossible to hack. China tech-policy experts say that initial focus likely came in response to the revelations in 2013 by former U.S. government contractor Edward Snowden that Washington had hacked deep into the backbone of China’s internet.

Since leaping ahead in its quest to build a hack-proof internet, Beijing’s shift of attention to quantum computing has been evident in the growing number of research projects and breakthroughs from Chinese scientists. The work has fed into a budding number of commercial efforts. Baidu relied on innovations from Chinese universities to build its computer, says Runyao Duan, the director of Baidu’s institute for quantum computing.

The U.S. still leads in the field, according to a 2022 analysis of scientific papers from Rand Corp. And Washington already has sought to slow China’s gains. Last year, the U.S. Commerce Department banned the export of high-tech equipment to eight Chinese companies and labs suspected of supporting China’s efforts to build quantum-based military applications. Broader export controls on equipment for making advanced silicon chips have also impacted quantum computers, which sometimes use silicon chips that rely on the same fabrication technologies.

Meanwhile, American academics say it’s gotten harder for Chinese students to obtain visas to conduct quantum research in the U.S. “It’s become common knowledge that when Chinese students or postdocs come to the U.S., they can’t say they’re doing quantum computing,” says Scott Aaronson, director of the Quantum Information Center at the University of Texas, Austin.

The Department of State didn’t respond to questions about its visa-issuance policy but said it considered the mobility of international students and researchers a priority. “We welcome students and scholars from countries around the world, including the People’s Republic of China,” a spokesperson said.

At the conference in Beijing where Qian Shi was unveiled, Yu Dapeng, dean of Shenzhen’s Institute for Quantum Science and Engineering, lamented the U.S.-imposed obstacles as well as internal challenges facing China’s continued quantum development. “There are a lot of people engaged in quantum, but it’s rare to see them have their own unique innovation or competitive technology,” Dr. Yu said.

Experts at Rand Corp. and elsewhere say China’s quantum computing advances have benefited the field globally, adding that more restrictions would slow the pace of scientific progress. Half of all published papers on quantum research result from international collaborations, and U.S. scientists co-author more quantum papers with scientists from China than any other country, the Rand Corp. analysis found.

A great deal of research remains to be done before quantum computers reach their full potential. Researchers estimate that building a quantum computer powerful enough to defeat existing data encryption protocols would require millions of qubits—a milestone that they say is likely a decade or more away. IBM, the industry leader today, has created a quantum computer with 127 qubits. Baidu says Qian Shi has 10 qubits and the company plans to release a 32-qubit computer next year.

Scientists around the world are now searching for ways to build more sophisticated quantum computers, including trying out different particles as qubits and using different methods to control them. Today’s most popular quantum computer design—the kind being developed by IBM, Google, Rigetti and now Baidu—relies on a device that cools a computer chip to ultralow temperatures, coaxing its electrons into a quantum state.

Companies are also looking for interim commercial applications, such as improving financial asset management or shipping route coordination, that might be possible with only hundreds or thousands of qubits, which quantum physicists are more confident will arrive in a few years.

Write to Karen Hao at karen.hao@wsj.com