A fast and scalable qubit-mapping method for noisy intermediate-scale quantum computers

Abstract

This paper presents an efficient qubit-mapping method that redesigns a quantum circuit to overcome the limitations of qubit connectivity. We propose a recursive graph-isomorphism search to generate the scalable initial mapping. In the main mapping, we use an adaptive look-ahead window search to resolve the connectivity constraint within a short runtime. Compared with the state-of-the-art method [15], our proposed method reduced the number of additional gates by 23% on average and the runtime by 68% for the three largest benchmark circuits. Furthermore, our method improved circuit stability by reducing the circuit depth and thus can be a step forward towards fault tolerance.