報告人：王曉光

主持人：嚴 冬

時  間：2021年6月22日上午9：30

地  點：綜合樓B區1306

主辦單位：長春大學理學院

報告人簡介：王曉光，浙江大學教授，長期從事量子信息論和量子物理基礎問題的研究，同時在量子光學和凝聚態理論中也進行了一系列的工作，在國內外學術刊物上共發表SCI收錄論文150篇，論文共被SCI他引5000余次。2001年發表在《物理評論A》上關于磁性系統海森堡XY模型中量子糾纏態的研究被SCI單篇引用600次，受到量子信息和凝聚態兩個領域研究人員高度重視，SCI引用次數超過100次的論文共有14篇。2011年Physics Reports上發表綜述性論文，量子自旋壓縮，系統評述了這個方向的最新進展（被引用300次）。2010年獲得國家基金委杰出青年科學基金資助，國務院特殊津貼獲得者。

觀點綜述：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.