Towards Effective Local Search for Qubit Mapping

• Published in: IEEE transactions on computers Vol. 74; no. 6; pp. 1897 - 1910
• Main Authors: Luo, Chuan, Cao, Shenghua, Guo, Shanyu, Hu, Chunming
• Format: Journal Article
• Language: English
• Published: IEEE 01.06.2025
• Subjects: Bridge circuits; Computers; Heuristic algorithms; local search; Logic gates; Noise measurement; Optimization; Performance evaluation; Qubit; Qubit mapping; Scalability; Search problems
• ISSN: 0018-9340; 1557-9956
• DOI: 10.1109/TC.2025.3544869

In the era of noisy intermediate-scale quantum (NISQ), a quantum logical circuit must undergo certain compilation before it can be used on a NISQ device, subject to connectivity constraints posed by NISQ devices. During compilation, numerous auxiliary quantum gates are inserted, but a circuit with too many is unreliable, necessitating gate minimization. This requirement gives rise to the qubit mapping problem (QMP), an NP-hard optimization problem that is critical in quantum computing. This work proposes a novel and effective local search algorithm dubbed EffectiveQM . First, EffectiveQM proposes a new mode-aware search strategy to alleviate the challenge of being trapped in local optima, where local search typically suffers. Moreover, EffectiveQM introduces a novel potential-guided scoring function, which can thoroughly quantify the actual benefit brought by an operation of inserting auxiliary gates. By incorporating the potential-guided scoring function, EffectiveQM can effectively determine the appropriate operation to be performed. Extensive experiments on a diverse collection of logical circuits and 6 NISQ devices demonstrate that EffectiveQM can generate physical circuits with significantly fewer inserted auxiliary gates than current state-of-the-art QMP algorithms, indicating that EffectiveQM greatly advances the state of the art in QMP solving.