Benchmarking Quantum Circuit Transformation With QKNOB Circuits

Current superconducting quantum devices impose strict connectivity constraints on quantum circuit execution, necessitating circuit transformation before executing quantum circuits on physical hardware. Numerous quantum circuit transformation (QCT) algorithms have been proposed. To enable faithful evaluation of state-of-the-art QCT algorithms, this article introduces qubit mapping benchmark with known near-optimality (QKNOB), a novel benchmark construction method for QCT. <monospace>QKNOB</monospace> circuits have built-in transformations with near-optimal (close to the theoretical optimum) <sc>swap</sc> count and depth overhead. <monospace>QKNOB</monospace> provides general and unbiased evaluation of QCT algorithms. Using <monospace>QKNOB</monospace>, we demonstrate that <monospace>SABRE</monospace>, the default Qiskit compiler, consistently achieves the best performance on the 53-qubit IBM Q Rochester and Google Sycamore devices for both <sc>swap</sc> count and depth objectives. Our results also reveal significant performance gaps relative to the near-optimal transformation costs of <monospace>QKNOB</monospace>. Our construction algorithm and benchmarks are open-source.