The Mercury News

How fast? Google touts quantum computing

Company says processor completed 10,000-year calculatio­n in mere minutes

- By Rachel Lerman and Matt O’Brien

SAN FRANCISCO >> 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 Na

ture, 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 are still a long way from having a practical applicatio­n but 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.” Google’s findings, however, are already facing pushback from other industry researcher­s. A version of Google’s paper leaked online last month and researcher­s caught a glimpse before it was taken down. IBM quickly took issue with Google’s claim that it had achieved “quantum supremacy,” a term that refers to a point when a quantum computer can perform a calculatio­n that a traditiona­l computer can’t complete

within its lifetime. Google’s paper shows that its quantum processor, Sycamore, finished a calculatio­n in three minutes and 20 seconds — and that it would take the world’s fastest supercompu­ter 10,000 years to do the same thing.

Google calculatio­n is a random sampling problem similar to dice roll or gambling machine to find outputs from a huge set of combinatio­ns of different numbers.

But IBM researcher­s say that Google underestim­ated the convention­al supercompu­ter, called Summit, and said it could actually do the calculatio­n in 2.5 days. Summit was developed by IBM and is located at the Oak Ridge National Laboratory in Tennessee.

Google dismissed IBM’s claims, asserting in a statement Wednesday that it performed its tests on an

“actual supercompu­ter” and is now on a “totally different trajectory” from classical computers. The company said Sycamore demonstrat­es that it is now “performing on real hardware a computatio­n that’s prohibitiv­ely hard for even the world’s fastest supercompu­ter, with more double exponentia­l growth to come.”

Whether or not Google has achieved “quantum supremacy” or not may matter to competitor­s, but the semantics could be less important for the field of quantum research. What it does seem to indicate is that the field is maturing.

“The quantum supremacy milestone allegedly achieved by Google is a pivotal step in the quest for practical quantum computers,” John Preskill, a Caltech professor who originally coined the “quantum

supremacy” term, wrote in a column after the paper was leaked.

It means quantum computing research can enter a new stage, he wrote, though a significan­t effect on society “may still be decades away.”

The calculatio­n employed by Google has little practical use, Preskill wrote, other than to test how well the processor works. Monroe echoed that concern.

“The more interestin­g milestone will be a useful applicatio­n,” he said.

The promise of such future applicatio­ns in commerce and national security has attracted interest from government­s including the United States and China that are increasing­ly investing in the expensive basic research needed to make quantum computers useful. One feared outcome of quantum computing —

though experts say it could be decades away — is a computer powerful enough to break today’s best cryptograp­hy.

President Donald Trump last year signed into law a congressio­nal proposal to spend $1.2 billion over five years for quantum research across the federal government.

Google’s research was centered at a UC Santa Barbara laboratory but relied in part on a Department of Energy supercompu­ter and experts at NASA to verify the work.

Ivanka Trump, the president’s daughter and adviser, on Wednesday called Google’s breakthrou­gh a “remarkable scientific achievemen­t” that will help usher in future U.S. industries.

 ?? GOOGLE VIA THE NEW YORK TIMES ?? Google CEO Sundar Pichai, left, and a researcher view Google’s quantum computer. Google said it had achieved “quantum supremacy,” which could allow computer calculatio­ns at speeds inconceiva­ble today.
GOOGLE VIA THE NEW YORK TIMES Google CEO Sundar Pichai, left, and a researcher view Google’s quantum computer. Google said it had achieved “quantum supremacy,” which could allow computer calculatio­ns at speeds inconceiva­ble today.

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