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A real-time, scalable, fast and resource-efficient decoder for a quantum computer

Abstract

The development of quantum computers will require the careful management of the noise effects associated with qubit performance. However, the decoders responsible for diagnosing noise-induced computational errors must use resources efficiently to enable scaling to large qubit counts and cryogenic operation. They must also operate at speed, to avoid an exponential slowdown in the logical clock rate of the quantum computer. To overcome these challenges, we introduce the Collision Clustering decoder and demonstrate its implementation on field-programmable gate array (FPGA) and application-specific integrated circuit (ASIC) hardware. We simulate logical memory experiments using the leading quantum error correction scheme (the surface code) and demonstrate megahertz decoding speed—matching the requirements of fast-operating modalities such as superconducting qubits—up to an 881 qubit surface code with the FPGA and 1,057 qubit surface code with the ASIC. The ASIC design occupies 0.06 mm2 and consumes only 8 mW of power.

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Fig. 1: Syndrome extraction circuit for a section of rotated planar code.
Fig. 2: CC decoder.
Fig. 3: Performance of our FPGA (Xilinx Ultrascale+ XCVU3P) implementation of the CC decoder on the rotated planar surface code.
Fig. 4: Modelling improvements to the CC algorithm for the next-generation FPGA decoder with P = 0.1%.

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Data availability

The stim32 circuits used to generate the samples and raw data from all the plots in this study are available via Zenodo at https://doi.org/10.5281/zenodo.11621877 (ref. 33).

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Acknowledgements

We thank S. Brierley and J. Taylor for encouraging this research and related discussions. We also thank M. Maragkou and L. Martiradonna for feedback on the manuscript.

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Contributions

K.M.B., N.I.G., K.J. and L.S. led the direction of the project with E.T.C. and B.B. providing guidance and advice. K.M.B., K.J. and L.S. developed the algorithm. K.M.B., K.J., A.W.R., L.S., M.L.T. and A.B.Z. developed software tools necessary to model the algorithm and its implementation on hardware. K.J. led T.B., O.B., R.R. and C.T. with the development of the hardware implementation of the decoder on the FPGA and ASIC, and the collection of the resulting data. L.S. analysed the data for both the hardware decoder and software models. K.M.B., T.B., N.I.G., K.J. and L.S. wrote an initial draft of the article. N.I.G. and L.S. wrote the final version of the article.

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Correspondence to Neil I. Gillespie or Luka Skoric.

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Nature Electronics thanks Blake Johnson and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Figs. 1–3 and Discussion.

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Barber, B., Barnes, K.M., Bialas, T. et al. A real-time, scalable, fast and resource-efficient decoder for a quantum computer. Nat Electron 8, 84–91 (2025). https://doi.org/10.1038/s41928-024-01319-5

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