DARPA boosts Microsoft’s far-out effort to build topological quantum computer
The Pentagon’s Defense Advanced Research Projects Agency is laying down a bet on Microsoft’s long-running effort to create an industrial-scale quantum computer that takes advantage of the exotic properties of superconducting nanowires.
Microsoft is one of three companies selected to present design concepts as part of a five-year program known as Underexplored Systems for Utility-Scale Quantum Computing, or US2QC. The DARPA program is just the latest example showing how government support is a driving force for advancing the frontiers of quantum computing — at a time when those frontiers are still cloaked in uncertainty.
“Experts disagree on whether a utility-scale quantum computer based on conventional designs is still decades away or could be achieved much sooner,” Joe Altepeter, US2QC program manager in DARPA’s Defense Sciences Office, said in a news release. “The goal of US2QC is to reduce the danger of strategic surprise from underexplored quantum computing systems.”
Altepeter said DARPA put out the call for companies to get in touch if they had an approach that they thought would lead to the creation of a useful general-purpose quantum computer in less than 10 years. “We offered to collaborate by funding additional experts to join their team and provide rigorous government verification and validation of their proposed solutions to determine its viability,” he said.
The result could lead to a “win-win,” Altepeter said: The companies’ commercial technologies would get a boost, while the federal government’s national security community could “avoid being surprised” by potentially disruptive effects.
The other companies joining Microsoft in the US2QC program are Atom Computing, which is working to harness the quantum properties of optically trapped atoms; and PsiQuantum, which is exploring the capabilities of silicon-based photonics. Both those companies are based in California.
In the program’s initial phase, each of the companies will present a design concept describing their plans to create a utility-scale quantum computer. Those concepts would guide the development of more rigorous, full-fledged system designs, which would be evaluated by a DARPA-led test and validation team.
Topological trickiness
The quantum quest involves an approach to computing that’s dramatically different from the traditional world of electronic ones and zeroes. Qubits, or quantum bits, can represent multiple values simultaneously until the results are read out. That makes quantum computing potentially more powerful for certain types of problems, such as sifting through large data sets to find optimal solutions.
Applications could include creating new chemicals for better batteries, more effective fertilizers or new types of drugs. Beyond chemistry, quantum computing could optimize systems ranging from traffic routes and interplanetary communication networks to financial services.
But what kind of hardware would be best suited for quantum computing? Microsoft has been exploring the potential of a topological qubit architecture for well more than a decade. Last year it reported a significant advance in its effort when it found evidence for an exotic phenomenon known as a Majorana zero mode.
A quantum computer based on Microsoft’s architecture would work by inducing and manipulating Majorana zero modes on the ends of topological superconducting wires. Demonstrating that such modes actually exist marked a big step toward turning Microsoft’s concept into reality.
Microsoft estimates that a quantum computer would have to have at least a million physical qubits in order to solve the sorts of problems that classical computers can’t handle. If those physical qubits aren’t the right size, the requisite hardware “could end up being the size of a football field,” Krysta Svore, vice president for advanced quantum development at Microsoft, said last week at the Northwest Quantum Nexus Summit.
“And so at Microsoft, we’ve been focusing on a qubit that’s just right, and that’s the topological qubit,” Svore said.
Last year’s findings boosted Microsoft’s confidence in its approach, but it’ll take much more research and development to produce a full-stack topological quantum computer. “We need the qubit that’s just right, and we need a system around it,” Svore said. “We need to integrate within the larger cloud, right? We need to integrate with an immense amount of classical computation. … At the same time, we need to also engineer and co-design software and hardware together.”
National security concerns
The federal government is interested in quantum computing for several reasons.
“The first goal of the U.S. is to promote this technology,” Charles Tahan, director of the National Quantum Coordination Office in the White House Office of Science and Technology Policy, said at last week’s summit. “We have to maintain our leadership in quantum information technology. That means more investment for R&D, more investment for workforce development programs, and more partnerships with the private sector but also [with] our international partners.”
Other goals relate to national security. “The one you would’ve seen in the news the most is moving the nation to quantum-resistant cryptography,” Tahan said.
Theoretically, quantum computers could solve challenges relating to large-number prime factorization, a branch of mathematics that plays a key role in secure online communications and financial transactions. “With the potential for a fault-tolerant quantum computer, if you had such a machine, you could break RSA and other forms of public-key cryptography,” Tahan said. “Given the time scales of how the nation must protect information for 25 years, even 50 years, it really is critical that we move to quantum-resistant cryptography now.”
Protecting information from quantum code-breaking is the flip side of figuring out how a quantum computer works. In the meantime, the federal government must protect U.S. technology from being stolen by global rivals, Tahan said.
“It’s going to take a decade or more to move to quantum-resistant cryptography, if we do it right,” he said. “While we’re doing that, we need to protect our investments, both for our economic security and our national security.”
China is the principal rival. Last month, Chinese researchers created a stir when they reported finding a way to crack the RSA algorithm that underlies most data encryption schemes. Outside experts said the resulting concerns were overblown; nevertheless, the report demonstrated how serious the stakes could get.
Peter Chapman, CEO of the IonQ quantum computer company, saw the Chinese claims as “a shot across the bow.”
“It just shows that … somebody could come out with a new idea and suddenly we’d be at risk,” Chapman said at last week’s summit. “So we need to be taking this much more seriously than we currently are today.”
Chapman said it will take federal support as well as private investment to ensure America’s leadership in the quantum quest. He can already point to an early example: IonQ’s collaboration with Pacific Northwest National Laboratory on a new method to produce barium ions for future quantum computers. The process will be part of the commercial supply chain as early as next year when IonQ ramps up operations at its research and manufacturing facility in Bothell, Wash.
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“How we win against places like China is going to be a public-private partnership, and the public side needs to be able to encourage the private side to invest in that. It is, if you will, the same thing that we did back at the beginning of semiconductors. There were a couple of companies like Fairchild that were busily working on integrated circuits, and NASA provided the initial market for those,” Chapman said. “Of course that provided the impetus to be able to invest in that particular technology. The rest is history, so to speak.”
So far, the public sector “has done a really good job with making sure the headlights are on” as tech companies drive down the quantum information superhighway, said Sebastian Hassinger, who’s in charge of worldwide business development and go-to-market strategy for quantum computing at Amazon Web Services.
“It’s not something you can leave to the private markets, essentially,” Hassinger told GeekWire. “You can see that just in how few venture funds are investing in quantum. It’s harder to do because it’s much longer horizons and much more uncertainty than the typical fund is set up to do. … It’s not three to five years till exit.”
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