How meaningful is D-Wave’s claim to quantum supremacy?

Canadian-born company D-Wave Quantum Systems said it achieved “quantum supremacy” last week after publishing what it calls a groundbreaking paper in the prestigious journal Science. Despite the lofty term, Canadian experts say supremacy is not the be-all, end-all of quantum innovation. 

D-Wave, which has labs in Palo Alto, Calif., and Burnaby, BC, claimed in a statement that it has shown “the world’s first and only demonstration of quantum computational supremacy on a useful, real-world problem.”

It is a very important and mostly academic metric, but certainly not the most important in the grand scheme of things.

Martin Laforest, Quantacet

Coined in the early 2010s by physicist John Preskill, quantum supremacy is the ability of a quantum computing system to solve a problem no classical computer can in a feasible amount of time. The metric makes no mention of whether the problem needs to be useful or relevant to real life. Google researchers published a paper in Nature in 2019 claiming they cleared that bar with the Sycamore quantum processor. Researchers at the University of Science and Technology in China claimed they demonstrated quantum supremacy several times. 

D-Wave’s attempt differs in that its researchers aimed to solve a real-world materials-simulation problem with quantum computing—one the company claims would be nearly impossible for a traditional computer to solve in a reasonable amount of time. D-Wave used an annealing designed to solve optimization problems. The problem is represented like an energy space, where the “lowest energy state” corresponds to the solution. 

While exciting, quantum supremacy is just one metric among several that mark the progress toward widely useful quantum computers, industry experts told BetaKit. 

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“It is a very important and mostly academic metric, but certainly not the most important in the grand scheme of things, as it doesn’t take into account the usefulness of the algorithm,” said Martin Laforest, managing partner at Quantacet, a specialized venture capital fund for quantum startups. 

He added that Google and Xanadu’s past claims to quantum supremacy were “extraordinary pieces of work, but didn’t unlock practicality.” 

Laforest, along with executives at Canadian quantum startups Nord Quantique and Photonic, say that the milestones of ‘quantum utility’ or ‘quantum advantage’ may be more important than supremacy. 

According to Quantum computing company Quera, quantum advantage is the demonstration of a quantum algorithm solving a real-world problem on a quantum computer faster than any classical algorithm running on any classical computer. On the other hand, quantum utility, according to IBM, refers to when a quantum computer is able to perform reliable computations at a scale beyond brute-force classical computing methods that provide exact solutions to computational problems. 

Julien Camirand Lemyre, CEO of Nord Quantique, said that in order to achieve supremacy, utility, or advantage consistently, companies must have “high-performance quantum error correction” to scale. Building large-scale quantum systems creates more and more errors, so achieving error correction at the qubit level, which is Nord Quantique’s focus, is key to useful quantum computing. 

A qubit, or quantum bit, is the basic unit of information for quantum systems, like binary bits composed of ones and zeros in classical computing. Qubits can exist in two states at once—zero and one—allowing for alternative, and in some cases accelerated, approaches to problem solving. 

Founded in 2020 out of Université de Sherbrooke, Nord Quantique develops processors for quantum computing. Last year, the startup claimed it achieved a new milestone for quantum error correction by integrating it into each qubit. 

A shifting term

Error correction hasn’t traditionally been considered a requirement for quantum supremacy, but Laforest told BetaKit the term is “an ever-moving target, constantly challenged by advances in classical algorithms.” He added: “In my opinion, some level of supremacy or utility may be possible in niche areas without error correction, but true disruption requires it.”

Paul Terry, CEO of Vancouver-based Photonic, thinks that though D-Wave’s claim to quantum supremacy shows “continued progress to real value,” scalability is the industry’s biggest hurdle to overcome.

“The critical question now is whether a given quantum computing architecture has a clear path to scaling to hundreds of thousands, or even millions, of high-quality logical qubits,” Terry wrote in an email to BetaKit. 

Photonic recently claimed it achieved a breakthrough in quantum error correction that could mean up to 20 times fewer qubits are needed for computations. 

D-Wave says that its quantum annealing approach tackles both error correction and enterprise problems at scale. 

But as with many milestone claims in the quantum space, D-Wave’s latest innovation has been met with scrutiny from industry competitors and researchers on the breakthrough’s significance, claiming that classical computers have achieved similar results. Laforest echoed this sentiment.

“Personally, I wouldn’t say it’s an unequivocal demonstration of supremacy, but it is a damn nice experiment that once again shows the murky zone between traditional computing and early quantum advantage,” Laforest said.

Originally founded out of the University of British Columbia, D-Wave went public on the New York Stock Exchange just over two years ago through a merger with a special-purpose acquisition company in 2022. D-Wave became a Delaware-domiciled corporation as part of the deal.

Earlier this year, D-Wave’s stock price dropped after Nvidia CEO Jensen Huang publicly stated that he estimated that useful quantum computers were more than 15 years away. D-Wave’s stock price, which had been struggling, has seen a considerable bump in recent months alongside a broader boost in the quantum market. The price popped after its most recent earnings, shared right after its quantum supremacy announcement. 

Image of D-Wave 2000Q Processors courtesy of D-Wave.