2 research outputs found
Control Requirements and Benchmarks for Quantum Error Correction
Reaching useful fault-tolerant quantum computation relies on successfully
implementing quantum error correction (QEC). In QEC, quantum gates and
measurements are performed to stabilize the computational qubits, and classical
processing is used to 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 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. Using a dynamical system
analysis, we show how the QEC control system latency performance determines the
operation regime of a QEC circuit: latency divergence, where quantum
calculations are unfeasible, classical-controller limited runtime, or
quantum-operation limited runtime where the classical operations do not delay
the quantum circuit. This analysis and the proposed benchmarks aim to allow the
evaluation and development of QEC control systems toward their realization as a
main component in fault-tolerant quantum computation.Comment: 21+9(SM) pages, 6+3(SM) figure
Quantum-classical processing and benchmarking at the pulse-level
Towards the practical use of quantum computers in the NISQ era, as well as
the realization of fault-tolerant quantum computers that utilize quantum error
correction codes, pressing needs have emerged for the control hardware and
software platforms. In particular, a clear demand has arisen for platforms that
allow classical processing to be integrated with quantum processing. While
recent works discuss the requirements for such quantum-classical processing
integration that is formulated at the gate-level, pulse-level discussions are
lacking and are critically important. Moreover, defining concrete performance
benchmarks for the control system at the pulse-level is key to the necessary
quantum-classical integration. In this work, we categorize the requirements for
quantum-classical processing at the pulse-level, demonstrate these requirements
with a variety of use cases, including recently published works, and propose
well-defined performance benchmarks for quantum control systems. We utilize a
comprehensive pulse-level language that allows embedding universal classical
processing in the quantum program and hence allows for a general formulation of
benchmarks. We expect the metrics defined in this work to form a solid basis to
continue to push the boundaries of quantum computing via control systems,
bridging the gap between low-level and application-level implementations with
relevant metrics.Comment: 22 page