The claim, made in a new scientific paper, is the most serious indication yet that the promise of quantum computers—an emerging but unproven type of machine—is becoming reality, including their potential to solve formerly ungraspable mathematical problems.
Essentially, Google purports to have pulled off a stunt on a quantum computer that no classical machine—not even the world’s most powerful supercomputer—can replicate.
A Google spokesperson declined to confirm the authenticity of the paper and its results. NASA did not respond immediately to a request for comment.
A source at Google familiar with the situation suggested, however, that NASA accidentally published the paper early, before its team’s claims could be thoroughly vetted through scientific peer review, a process that could take anywhere from weeks to months.
If the paper holds up under the scrutiny of the scientific community, it will herald a watershed moment in quantum science. Its central claim counters doubt that some unforeseen law of nature may prevent quantum computers from operating as hoped.
“Quantum speedup is achievable in a real-world system and is not precluded by any hidden physical laws,” the Google researchers write.
Further, they predict that quantum computing power will “grow at a double exponential rate,” besting even the exponential rate that defined Moore’s Law, a trend that observed traditional computing power to double roughly every two years.
The experiment described in the paper sampled randomly generated numbers produced through a specialized scenario involving quantum phenomena. The researchers said they determined that their quantum computer beat regular computers at the task, which involved calculating the output of certain specialized circuits.
“While our processor takes about 200 seconds to sample one instance of the quantum circuit 1 million times, a state-of-the-art supercomputer would require approximately 10,000 years to perform the equivalent task,” the researchers said.
Google’s quantum computer, dubbed “Sycamore,” contained 53-qubits, or “quantum bits,” a measure of the machine’s potential power. The team scaled back from a 72-qubit device, dubbed “Bristlecone,” it had previously designed.
The researchers estimate that performing the same experiment on a Google Cloud server would take 50 trillion hours—too long to be feasible. On the quantum processor, it took only 30 seconds, they said.
“Quantum processors based on superconducting qubits can now perform computations…beyond the reach of the fastest classical supercomputers available today,” the researchers write. “To our knowledge, this experiment marks the first computation that can only be performed on a quantum processor.”