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Sherbrooke, Québec-based Nord Quantique claims that it has achieved a new milestone for error correction in quantum computing.

The early-stage startup, which is developing processors for quantum computing, announced results from its latest research paper this morning. Nord Quantique says it has demonstrated the ability to reduce errors on a single qubit by 14 percent, without relying on the traditional method of using additional qubits to do so.

“It’s one thing to build a quantum computer, it’s another one to make it useful.”

Philippe St-Jean, Nord Quantique

​Though some in academia, including pioneering researchers at Yale University, have achieved similar results already, Nord Quantique co-founder and CEO Philippe St-Jean told BetaKit this milestone is still “a huge deal” for the startup. “It’s the first time that a company [has] actually [been] able to do that, which we’re really proud of because we were able to get there in essentially a couple of years,” he said in an interview.

St-Jean is hopeful Nord Quantique’s hardware-efficient approach will yield a shorter, cheaper, and more scalable path to full-blown, fault-tolerant quantum computers, requiring hundreds of qubits rather than the millions he predicts physical redundancy-based strategies will need. 

Founded by St-Jean and CTO Julien Camirand Lemyre, Nord Quantique was spun out of Québec’s University of Sherbrooke and its Institut Quantique in 2020 and is currently based in Sherbrooke’s Quantum Innovation Zone. This news comes two years after Nord Quantique closed $9.5 million CAD in seed funding from BDC Capital’s Deep Tech Venture Fund, Quantonation, and Real Ventures.

Qubits—or quantum bits—are the most basic unit of information in quantum computing. But that quantum information is fragile: environmental factors or ‘noise’ on chips can produce errors at the qubit level. Many quantum computer developers have dedicated extra qubits to the correction of these errors, creating physical redundancy.

Rather than build larger processors with more qubits to correct these errors, Nord Quantique has taken a different approach, developing bosonic codes implemented with superconducting circuits. By applying those codes to qubits, Nord Quantique aims to reduce errors without the need for additional qubits. The startup’s latest results signal that this strategy might just work.

According to Nord Quantique, simulations it has run indicate that these results can be reproduced with additional qubits, and that “there is likely to be significant further improvement in error correction as the number of qubits increases.” 

RELATED: Nord Quantique closes $9.5-million seed round co-led by BDC Capital’s Deep Tech fund

Over the past decade, more and more companies have set out to build quantum computers and the hardware to enable them, including fellow Canadian firms like D-Wave, Photonic, and Xanadu. But quantum computers capable of solving practical problems are still not here yet. The big challenge remains error correction, says St-Jean.

“One of the issues that has come to light over the last 10 years or so is that it’s one thing to build a quantum computer, it’s another one to make it useful—in part because [they are] very sensitive to [their] environment,” said St-Jean.

Even the smallest environmental interaction can create errors in the computation, said St-Jean, who noted that this is why quantum computing systems typically run at very low temperatures in cryo-fridges.

There are ways to tackle this problem. According to St-Jean, the approach many players are taking involves creating physical redundancy. “Instead of using just one qubit … you use many,” he added, noting that this strategy entails repeating information across qubits at a “10-to-one factor,” creating one logical qubit.

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“We’re talking about 1,000 to 10,000 physical qubits, physical elements, just to encode the equivalent of one logical working one that wouldn’t make errors.”

This strategy has its drawbacks—namely, scalability—said St-Jean, who described it as impractical, expensive, and time-intensive. “It’s already a challenge to build a system with a few hundred physical qubits.”

This is something that deep-pocketed, resource-rich tech giants like IBM and Google have been able to achieve. But getting to the millions of qubits necessary to start doing useful computation will take “way too much time,” argued St-Jean.

St-Jean and Nord Quantique are hopeful that the startup’s approach to quantum error correction will prove more scalable in the long run. The company plans to unveil results from its multi-qubit system later this year.

Feature image courtesy Nord Quantique.