Control Requirements and Benchmarks for Quantum Error Correction

Reaching fault-tolerant quantum computation depends on the successful implementation of quantum error correction (QEC). In QEC, quantum gates and measurements are performed to stabilize the computational qubits, while classical computations convert the measurements into estimated logical Pauli frame updates or logical measurement results. While QEC research has concentrated on developing and evaluating QEC codes and decoding algorithms, specification and clarification of the requirements for the classical control system running QEC codes are lacking. Here, we elucidate the roles of the QEC control system, the necessity to implement low latency and parallelizable feed-forward quantum operations, and suggest near-term benchmarks that confront the classical bottlenecks for QEC quantum computation. These benchmarks are based on the latency between a measurement and the operation that depends on it, and incorporate the different control aspects such as quantum-classical parallelization capabilities and decoding throughput. The proposed benchmarks aim to allow the evaluation and development of scalable building blocks of QEC control system toward its realization as a main component in fault-tolerant quantum computing.