Breakthrough removes a major bottleneck in fault-tolerant quantum computing, enabling real-time error correction across millions of operations without slowing down execution time.
COLLEGE PARK, Md., Sept. 22, 2026: IonQ (NYSE: IONQ), the world’s leading full-stack quantum platform and foundry, today announced a major milestone in fault-tolerant quantum computing. Researchers demonstrated the development and successful testing of the industry’s first end-to-end real-time quantum error correction decoder that runs on a single standard off-the-shelf central processing unit (CPU).
Quantum error correction is essential for building practical, fault-tolerant quantum computers because physical qubits are inherently sensitive to environmental noise. However, finding and fixing those errors in real time has historically presented a significant computing challenge. In conventional approaches, the classical computers tasked with decoding errors can easily become overwhelmed. That creates a processing bottleneck that forces the quantum computer to pause and wait. IonQ’s breakthrough demonstrates that a single, standard computer processor can manage this complex workload continuously in the background, keeping the quantum system running at full speed.
“Successfully validating real-time decoding across hundreds of logical qubits and over millions of logical operations is an important milestone. Moreover, the fact that our decoder runs on a single CPU provides a practical path to commercial-scale fault-tolerant quantum computing,” said Nicolas Delfosse, paper co-author and quantum research lead at IonQ.
In technical research published on arXiv, IonQ evaluated its dual-decoder architecture across complex benchmark circuits simulating up to 408 logical qubits across 88 memory blocks and magic factories. These circuits were executing more than 31.5 million individual quantum operations at the ‘MegaQuOp’ scale. Under standard operational noise, IonQ’s decoder introduced as little as 0.02% ‘stretch’ time. That means the decoding overhead added virtually no delay to the overall quantum computation.
“IonQ is enabling cost-effective quantum system scaling through direct verification of each component,” said John Gamble, Vice President at IonQ Architecture.
This achievement validates a core pillar of IonQ’s proprietary Walking Cat architecture and confirms that classical hardware overhead does not need to scale exponentially as quantum systems grow wider in logical qubits or deeper in operations. The breakthrough establishes a key technological foundation for IonQ’s roadmap beyond 256 physical qubits toward industrial-scale platforms controlling thousands of qubits.
Source: IonQ, 22 September 2026.
