Quantum computing decoder and associated methods

An apparatus for decoding syndromes of a quantum error correction code, the apparatus comprising:

• a plurality of block decoders;
• a process manager configured to:
• receive syndrome measurement data comprising a plurality of quantum error correction rounds performed on a plurality of qubits of a quantum computer;
• identify a plurality of primary blocks of the syndrome measurement data, wherein neighbouring primary blocks are separated by interstitial blocks of quantum error correction rounds, each primary block comprising:
• a first central block of quantum error corrections rounds;
• and
• a first buffer block of quantum error correction rounds, wherein the first buffer block surrounds the first central block;
• provide each one of the primary blocks to a respective block decoder of the plurality of block decoders and each one of the interstitial blocks to a respective block decoder of the plurality of block decoders,
• wherein each respective block decoder provided with a respective primary block is configured to:
• identify the location of errors in the plurality of qubits by decoding the respective primary block to provide a respective decoded first central block and a respective decoded first buffer block;
• provide the location of the errors in the respective decoded first central block to an output;
• provide at least a first part of the respective decoded first buffer block to the respective block decoder with the particular interstitial block immediately preceding the respective primary block;
• provide at least a second part of the decoded first buffer block to the respective block decoder with the particular interstitial block immediately succeeding the respective primary block.