Quantum walks on a programmable two-dimensional 62-qubit superconducting processor

Ming Gong, Shiyu Wang, Chen Zha, Ming-Cheng Chen, He-Liang Huang, Yulin Wu, Qingling Zhu, Youwei Zhao, Shaowei Li, Shaojun Guo, Haoran Qian, Yangsen Ye, Fusheng Chen, Jiale Yu, Daojing Fan, Dachao Wu, Hong Su, Hui Deng, Hao Rong, Jin Lin, Yu Xu, Lihua Sun, Cheng Guo, Futian Liang, Kae Nemoto, W. J. Munro, Chao-Yang Lu, Cheng-Zhi Peng, Xiaobo Zhu, Jian-Wei Pan

Published 2021-02-04Version 1

Quantum walks are the quantum mechanical analogue of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing. In our work, we have designed and fabricated an 8x8 two-dimensional square superconducting qubit array composed of 62 functional qubits. We used this device to demonstrate high fidelity single and two particle quantum walks. Furthermore, with the high programmability of the quantum processor, we implemented a Mach-Zehnder interferometer where the quantum walker coherently traverses in two paths before interfering and exiting at a single port of it. By tuning the disorders of the sites on the evolution paths, we observed interference fringes with single and double walkers. Our successful demonstration of a programmable quantum walks on a two-dimensional solid-state system is an essential milestone in the field, brings future larger scale quantum simulations closer to realization, and also highlights the potential of another model of universal quantum computation on these NISQ processors.