Qubit mapping: the adaptive divide-and-conquer approach
摘要
The qubit mapping problem (QMP) addresses the routing of qubits in quantum circuits to comply with the limited connectivity of near-term quantum hardware. Solving QMP is a key step in quantum circuit compilation and is known to be NP-complete. This paper proposes a novel approach called adaptive divide-and-conquer (ADAC), which uses subgraph isomorphism check to partition the circuit and construct the initial mapping and employs a heuristic search strategy for efficient qubit routing. Extensive experiments on various NISQ architectures demonstrate that ADAC significantly outperforms state-of-the-art methods. For example, on IBM Tokyo, it achieves over 50% SWAP gate reduction on realistic benchmarks from RevLib and Qiskit. Although ADAC incurs additional runtime and memory usage due to its quality-focused design, these overheads remain well within practical limits, especially for near-term quantum circuits with moderate gate counts. Crucially, the resource cost scales more with gate count than with qubit count, making ADAC both efficient and scalable for small- to medium-sized circuits. Its high mapping quality and consistent performance render it particularly suitable for offline compilation workflows, benchmarking, and fidelity-sensitive quantum applications. Overall, ADAC represents a robust and scalable framework for structure-aware quantum circuit transformation.