报告人：王晓光

主持人：严 冬

时  间：2021年6月22日上午9：30

地  点：综合楼B区1306

主办单位：长春大学理学院

报告人简介：王晓光，浙江大学教授，长期从事量子信息论和量子物理基础问题的研究，同时在量子光学和凝聚态理论中也进行了一系列的工作，在国内外学术刊物上共发表SCI收录论文150篇，论文共被SCI他引5000余次。2001年发表在《物理评论A》上关于磁性系统海森堡XY模型中量子纠缠态的研究被SCI单篇引用600次，受到量子信息和凝聚态两个领域研究人员高度重视，SCI引用次数超过100次的论文共有14篇。2011年Physics Reports上发表综述性论文，量子自旋压缩，系统评述了这个方向的最新进展（被引用300次）。2010年获得国家基金委杰出青年科学基金资助，国务院特殊津贴获得者。

观点综述：The quantum multiparameter estimation is very different from the classical multiparameter estimation due to Heisenberg’s uncertainty principle in quantum mechanics. When the optimal measurements for different parameters are incompatible, they cannot be jointly performed. We find a correspondence relationship between the inaccuracy of a measurement for estimating the unknown parameter with the measurement error in the context of measurement uncertainty relations. Taking this correspondence relationship as a bridge, we incorporate Heisenberg’s uncertainty principle into quantum multiparameter estimation by giving a trade-off relation between the measurement inaccuracies for estimating different parameters. For pure quantum states, this trade-off relation is tight, so it can reveal the true quantum limits on individual estimation errors in such cases. We apply our approach to derive the trade-off between attainable errors of estimating the real and imaginary parts of a complex signal encoded in coherent states and obtain the joint measurements attaining the trade-off relation. We also show that our approach can be readily used to derive the trade-off between the errors of jointly estimating the phase shift and phase diffusion without explicitly parametrizing quantum measurements.