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Google's Quantum Supremacy Claim Has Practical Implications

Google researchers claimed to have reached a major milestone in the evolution of quantum computing called "quantum supremacy" in a paper published last week in the journal Nature. IBM quickly disputed that claim in a blog post that threw shade on the Alphabet subsidiary's conclusions. The headlines they generated notwithstanding, the claim and counterclaim involve a branch of computing most industry watchers say is still in the budding stage, so why should anyone care who's right?

"Whether or not Google achieved true quantum supremacy or it's more like quantum advantage, what's exciting here is that what they did shows real progress," said Gartner analyst Matthew Brisse. "Assuming the paper survives scrutiny by all the academic folks, this is a fantastic achievement by Google."

Brisse is a Research Vice President for the Data Center and Cloud Infrastructure group within the Gartner for Technical Professionals service. He provides strategic and technical advice for CIOs and tech pros on a range of topics, including quantum computing. Gartner currently has several analysts tracking 62 companies in the quantum computing space, he said, from hardware and software providers to consultants.

"Our guidance to CIO's is that they shouldn't ignore this space, because it's likely to be a real competitive differentiator in five to ten years," he said. "But they wouldn't want to go all in just yet, because it's not clear exactly what it's going to do for them. Let the hardware and software mature, let the algorithms start unfolding. But don't throw a lot of money at it now."

Developers, however, should take the leap sooner rather than later, Brisse advises.

"If you're a programmer interested in quantum computing, get involved now," he said. "Take advantage of the free quantum systems that are available -- things like Microsoft's QDK, D-Wave System's Ocean SDK, Rigetti's Forest SDK, and IBM's Qiskit. Microsoft has developed a domain-specific programming language for expressing quantum algorithms called Q#. And there's a plethora of libraries out there. They should check out the Quantum Algorithm Zoo, for example, which is a repository of quantum algorithms."

The Quantum Open Source Foundation maintains a curated list of open-source quantum software projects on GitHub. Last month, IBM opened a quantum computational center in Poughkeepsie, New York, designed to "support the growing needs of a community of over 150,000 registered users and nearly 80 commercial clients, academic institutions, and research laboratories to advance quantum computing and explore practical applications," the company said in a statement.

Another reason to get started now, Brisse said, is that quantum computing is complicated. It takes time to learn quantum computing algorithm development, and mapping business problems to quantum computing is difficult to get right. Plus, there's a lot of physics involved.

"There's a shortage of physicists in the industry today who know computers and business," Brisse said. "So we're seeing organizations like Microsoft and IBM actually going into the universities and cultivating a new type of quantum computing engineer."

Gartner defines quantum computing as a type of "nonclassical" computing that operates on the quantum state of subatomic particles. The particles represent information as quantum bits (qubits). In classical computing, bits represent information as either 0s or 1s; qubits represent both at the same time until they are read, thanks to a quantum state called superposition. Qubits can be linked with other qubits, thanks to another quantum property called entanglement. As Gartner explains it, "Quantum algorithms manipulate linked qubits in their undetermined, entangled state, a process that can address problems with vast combinatorial complexity."

In other words, quantum computing has the potential to solve some of mankind's greatest technical and scientific puzzles and problems. That potential might explain why companies like Google, IBM, Intel, and others are investing heavily in the technology. An analysis by Nature found that in 2017 and 2018 quantum technology companies received at least $450 million in private funding, a fourfold increase from the $104 million of the previous two years.

So Google's efforts are about more than just bragging rights to the coveted quantum supremacy, a kind of black belt earned by computing devices that can solve problems no classical computer can handle. (Quantum advantage is the brown belt; faster, but not unbeatable, though it's sometimes used as a synonym.) In that peer-reviewed Nature article, Google researchers describe how a team led by experimental physicist John Martinis used Google's Sycamore, a 53-qubit quantum processor, to solve a random number generation problem in 200 seconds, a calculation they said would take a state-of-the-art supercomputer 10,000 years to complete.

"For those of us working in science and technology, it's the 'hello world' moment we've been waiting for," wrote Google CEO Sundar Pichai in a blog post, "the most meaningful milestone to date in the quest to make quantum computing a reality."

In its quickly published rejoinder, IBM claimed that its Summit supercomputer, which it built for the Department of Energy, can do the calculation in two and a half days with greater fidelity.

"This is, in fact, a conservative, worst-case estimate, and we expect that with additional refinements the classical cost of the simulation can be further reduced," Big Blue's team wrote. "Because the original meaning of the term 'quantum supremacy,' as proposed by John Preskill in 2012, was to describe the point where quantum computers can do things that classical computers can't, this threshold has not been met."

Preskill, a professor of theoretical physics at the California Institute of Technology, wrote about Google's claim and the apparently controversial term he coined in a recent Quanta Magazine column. He regrets how the word "exacerbates the already overhyped reporting on the status of quantum technology," he wrote. But that didn't stop him from coining another term a few sentences later. The term is "NISQ," which rhymes with "risk" and stands for "noisy intermediate-scale quantum."

"Here intermediate-scale refers to the size of quantum computers that are now becoming available: potentially large enough to perform certain highly specialized tasks beyond the reach of today's supercomputers," he explained. "Noisy emphasizes that we have imperfect control over the qubits, resulting in small errors that accumulate over time; if we attempt too long a computation, we're not likely to get the right answer."

"The Google team has apparently demonstrated that it's now possible to build a quantum machine that's large enough and accurate enough to solve a problem we could not solve before," he added, "heralding the onset of the NISQ era."

Posted by John K. Waters on October 29, 2019