Google declares quantum computing leap

Google has announced a quantum processor had completed a calculation that would take supercomputers thousands of years in just a few minutes.

Rachel Lerman and Matt O’Brien reported the news for the AP:

Google said it has achieved a breakthrough in quantum computing research, saying an experimental quantum processor has completed a calculation in just a few minutes that would take a traditional supercomputer thousands of years.

The findings, published Wednesday in the scientific journal Nature, show that “quantum speedup is achievable in a real-world system and is not precluded by any hidden physical laws,” the researchers wrote.

Quantum computing is a nascent and somewhat bewildering technology for vastly sped-up information processing. Quantum computers might one day revolutionize tasks that would take existing computers years, including the hunt for new drugs and optimizing city and transportation planning.

The technique relies on quantum bits, or qubits, which can register data values of zero and one — the language of modern computing — simultaneously. Big tech companies including Google, Microsoft, IBM and Intel are avidly pursuing the technology.

“Quantum things can be in multiple places at the same time,” said Chris Monroe, a University of Maryland physicist who is also the founder of quantum startup IonQ. “The rules are very simple, they’re just confounding.”

Emily Conover from Science News noted:

The researchers performed the task with a chip consisting of only 53 qubits, the quantum version of the bits found in everyday computers. “It’s fascinating that we can do something so powerful with such a small chip,” says quantum physicist Mária Kieferová of the University of Technology Sydney, who was not involved with the study. 

But don’t expect quantum computers to suddenly take over. The calculation Google’s quantum computer performed was not a particularly useful one. Instead, the task at hand was one that was designed to play to quantum computers’ strengths and to be difficult for a nonquantum, or “classical,” computer.

What’s more, some researchers are pushing back against Google’s quantum supremacy claim, arguing that the milestone has yet to be achieved. 

For about a month, rumors have been swirling among scientists that Google would soon report its achievement of quantum supremacy (SN: 9/21/19). The company’s official announcement, in a study published October 23 in Nature, follows the apparently unintentional posting of an earlier version of the study on a NASA website in September. That paper was swiftly taken down, but copies of it persisted and were shared among researchers.

The concept of quantum supremacy, proposed in 2012 by theoretical physicist John Preskill, has attracted controversy. The term lends itself to hype, and some quantum physicists prefer to focus on metrics that imply practical usefulness — which supremacy does not. 

Wired’s Tom Simonite, however, quoted IBM as saying Google rigged the test:

In a technical paper and blog post, IBM took aim at potentially history-making scientific results accidentally leaked from a collaboration between Google and NASA last month. That draft paper claimed Google had reached a milestone dubbed “quantum supremacy”—a kind of drag race in which a quantum computer proves able to do something a conventional computer can’t.

Monday, Big Blue’s quantum PhDs said Google’s claim of quantum supremacy was flawed. IBM said Google had essentially rigged the race by not tapping the full power of modern supercomputers. “This threshold has not been met,” IBM’s blog post says. Google declined to comment.

It will take time for the quantum research community to dig through IBM’s claim and any responses from Google. For now, Jonathan Dowling, a professor at Louisiana State University, says IBM appears to have some merit. “Google picked a problem they thought to be really hard on a classical machine, but IBM now has demonstrated that the problem is not as hard as Google thought it was,” he says.

Whoever is proved right in the end, claims of quantum supremacy are largely academic for now. The problem crunched to show supremacy doesn’t need to have immediate practical applications. It’s a milestone suggestive of the field’s long-term dream: That quantum computers will unlock new power and profits by enabling progress in tricky areas such as battery chemistry or health care. IBM has promoted its own quantum research program differently, highlighting partnerships with quantum-curious companies playing with its prototype hardware, such as JP Morgan, which this summer claimed to have figured out how to run financial risk calculations on IBM quantum hardware.