The accurate implementation of quantum gates is essential for the realisation of quantum algorithms and digital quantum simulations. This accuracy may be increased on noisy hardware through the variational optimisation of gates, however the experimental realisation of such a protocol is impeded by the large effort required to estimate the fidelity of an implemented gate. With a hierarchy of approximations we find a faithful approximation to the quantum process fidelity that can be estimated experimentally with reduced effort. Its practical use is demonstrated with the optimisation of a three-qubit quantum gate on a commercially available quantum processor.
Sharpening Worst-Case Error Assessment for Fault-Tolerant Quantum Computing: Fidelity and Its Deviation
Institute for Convergence Research and Education in Advanced Technology, Yonsei University（延世大学先进技术与教育融合研究所）；Department of Statistics and Data Science, Yonsei University（延世大学统计与数据科学系）；Quantum Network Research Center, Korea Institute of Science and Technology Information（韩国科学技术信息研究院量子网络研究中心）；Electronics and Telecommunications Research Institute（电子通信研究院）；Department of Quantum Information, Yonsei University（延世大学量子信息系）
Quality assessment of quantum teleportation through the distribution of fidelity
Universidad de Valladolid（巴利亚多利德大学）；CONICET-Universidad de Buenos Aires, Instituto de Ciencias de la Computación (ICC)（阿根廷国家科学研究委员会-布宜诺斯艾利斯大学，计算科学研究所）；Jagiellonian University（雅盖隆大学）；Center for Theoretical Physics, Polish Academy of Sciences（波兰科学院理论物理中心）
