Parallel decoding for quantum error correcting codes

A system comprising:

• a classical computer system configured to implement a decoding process on measurement data received from a quantum computing system to determine errors in a quantum computation implemented by the quantum computing system, wherein the classical computing system implements:
• a main thread;
• multiple worker threads;
• and
• a data structure common to each worker thread of the multiple worker threads, wherein the data structure stores data of a dynamic system of disjoint clusters of nodes of a detector graph for the decoding process, wherein:
• each cluster of nodes comprises a root node that has no ascendant node and one or more descending child nodes, wherein the child nodes include leaf nodes with no descending nodes or one or more descending child nodes;
• and
• the data comprises compressed logical flip information of child nodes in each cluster of nodes;
• wherein during execution of the decoding process, each of the multiple worker threads is configured to, in parallel with each of the other worker threads:
• obtain, from the main thread, one or more clusters of nodes in the detector graph, wherein each cluster of nodes comprises one or more detection events in the measurement data;
• and
• execute the decoding process to modify the one or more clusters of nodes, wherein, for each modification of a cluster, the worker thread updates data in the data structure that corresponds to the cluster under an atomicity primitive.