题目：Hybrid Shadow Estimation: Theory and Experiment
报告人：周游 副研究员
主持人：吴典 研究员
时间：2024年9月23日（周一）14:00
地点：闵行校区光学大楼B325会议室
报告人简介：
周游是复旦大学信息科学与工程学院、电磁波信息科学教育部重点实验室青年副研究员，研究领域是量子信息与计算基础理论。2014年本科毕业于浙江大学信电系，2019年清华大学交叉院获博士学位，曾在中国科大、哈佛大学、南洋理工大学从事访问学者和博士后研究。研究兴趣包括量子纠缠与关联、量子系统标定与错误抑制，量子模拟算法等，已在PRL，npj-QI，Quantum等期刊发表27篇学术论文，其中18篇（共同）第一/通讯作者。
报告内容简介：
Estimating nonlinear functions of quantum states, such as the moment and entanglement, is of fundamental and practical interest in quantum science and technology. In this talk, I would introduce our recent theoretical proposal and its experimental demonstration on this topic. The theoretical work [npj Quantum Information(2024)] introduces the hybrid shadow (HS) estimation frameworkfor measuring general nonlinear functions, which combines swap test and randomized measurements. Such hybrid framework utilizes the partial coherent power of the intermediate-scale quantum processor and dramatically reduces measurement and postprocessing costs. We analytically and numerically demonstrate advantages in tasks of state-moment estimation and quantum error mitigation. In the collaborative experimental work [arXiv:2404.11850], we implement HS in an optical system via designing and realizing a deterministic quantum Fredkin gate over multiple degrees of freedom of a single photon. We demonstrate HS in the estimations of higher-order functions and further apply it in a proof-of-principle quantum metrology experiment, where the accuracy of parameter estimation is enhanced with the assistance of virtual distillation. Our results suggest that HS is an efficient and powerful tool for shadow-estimation-enabled quantum information processing.