Prototype quantum processor boasts record 99.9% qubit fidelity

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IQM's quantum processor achieved 99.9% fidelity in recent tests, the company says, edging the previous 99.8% record it set in February. Here's what that actually means.

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The technology from the prototype two-qubit device will be integrated into existing and future quantum processors like the 20-qubit chip (pictured) that was built earlier this year. (Image credit: IQM)

Scientists in Finland say they have made inroads toward "fault-tolerant" quantum computing after achieving record-low error rates in a prototype quantum processor — potentially paving the way to more practical and stable quantum computers.

In a statement, researchers at IQM Quantum Computers said their technology had broken ground in two key areas: the accuracy of operations between qubits — the most basic units of quantum information — and the stability of qubits over time.

IQM representatives said scientists had achieved 99.9% fidelity in two-qubit gate operations and hit a new record in "qubit relaxation time," meaning the time it takes for a qubit to lose its quantum state.

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These achievements bring fault-tolerant quantum computing — where errors in quantum calculations correct themselves automatically — closer to reality, IQM representatives said. This was particularly apparent in testing the quantum gates.

Quantum gates are the building blocks of quantum circuits, similar to logic gates in classical computers. Logic gates are digital switches that act as decision-makers in computers, using binary data (1s and 0s) to perform basic operations.

High fidelity in two-qubit gates are key for generating entangled states — when qubits become interconnected in such a way that the state of one directly affects the state of the other, regardless of the distance between them. Quantum entanglement is a cornerstone of quantum mechanics and what Einstein dubbed "spooky action at a distance."

For the test, the coherence times were measured by the relaxation time (T1) and the dephasing time (T2). These refer to how long a qubit can retain its quantum state before it returns to its normal state and how long a qubit can stay in sync with other qubits, respectively.

IQM recorded a T1 of 0.964 millisecond, with a possible variation of 0.092 millisecond, and a T2 of 1.155 millisecond with a 0.188-millisecond variable. This means the qubits maintained their information and quantum state for nearly 1 millisecond.

While this doesn't sound like a lot, it is considerable in the world of quantum operations, where typical coherence times are often on the order of microseconds. IBM's 127-qubit Eagle processor, for instance, can manage coherence times of just over 400 microseconds.

"The significance of these results stems from the fact that only very few organizations have achieved comparable performance numbers before," IQM representatives said in the statement.

If this technology is integrated into a future quantum processor, it can be used in more complex use cases than IQM's 20-qubit quantum computer — its most powerful machine today. The researchers plan to explore potential applications in fields such as machine learning, cybersecurity, route optimization, quantum sensor simulation and health care.

Owen Hughes
Owen Hughes

Owen Hughes is a freelance writer and editor specializing in data and digital technologies. Previously a senior editor at ZDNET, Owen has been writing about tech for more than a decade, during which time he has covered everything from AI, cybersecurity and supercomputers to programming languages and public sector IT. Owen is particularly interested in the intersection of technology, life and work ­– in his previous roles at ZDNET and TechRepublic, he wrote extensively about business leadership, digital transformation and the evolving dynamics of remote work.