IQM Quantum Computers has developed a new quantum error-correcting code that it says can reduce logical error rates by up to 1,000 times compared with the widely used surface code while requiring up to eight times fewer physical qubits.

The company said the new approach, called barbell codes, could help address one of the biggest challenges facing quantum computing: correcting errors quickly enough to enable large-scale, fault-tolerant machines.

Quantum computers are highly sensitive to noise, which can introduce errors during calculations. To overcome this, researchers use quantum error correction, a process that spreads information across multiple physical qubits to create more reliable logical qubits. However, existing methods often require large numbers of qubits and increasingly complex hardware.

According to IQM, its new code aims to improve both efficiency and practicality by lowering error rates while reducing the number of physical qubits needed to protect quantum information.

Fewer qubits, fewer errors

The barbell code family was designed specifically for IQM’s Constellation processor architecture, which features enhanced connectivity between qubits. In the system, each qubit can directly interact with up to 12 neighboring qubits, compared with four in a conventional square-grid arrangement.

The company said the design allows high-performance error correction without requiring extensive additional hardware. Barbell codes rely on a single long coupler connection for every second qubit, reducing the need for multiple long-range crossing couplers that can complicate chip fabrication.

By taking advantage of the processor’s connectivity, the code can generate the entanglement needed for error correction while keeping hardware requirements comparatively low.

“We are pioneering the next chapter in quantum computing,” said Jan Goetz, CEO and Co-founder of IQM Quantum Computers.

“Our approach offers a highly competitive path to scalable quantum error correction with superconducting qubits, paving the way for large-scale, fault-tolerant quantum computers.”

The company said the approach is intended for real-world superconducting quantum processors rather than idealized laboratory systems, with an emphasis on manufacturability and scalability.

Building practical quantum

Error correction is widely considered one of the key hurdles preventing today’s quantum computers from tackling commercially valuable problems at scale. While advances in qubit quality have steadily improved hardware performance, experts believe fault-tolerant systems will require robust error-correction schemes capable of suppressing errors faster than they accumulate.

IQM claims its barbell codes offer a path toward that goal by combining lower logical error rates with lower hardware complexity. The company said the technology supports its roadmap toward quantum systems capable of operating with hundreds of high-precision logical qubits.

The development comes as IQM prepares to deploy 150-qubit quantum systems to customers later this year. The company has also announced IQM Halocene, a quantum computer designed for testing and developing error-correction technologies.

If the reported performance gains can be replicated in large-scale systems, the new approach could help reduce the hardware overhead traditionally associated with fault-tolerant quantum computing.

The development details and numerical performance analysis were published on arXiv.