中国物理B ›› 2026, Vol. 35 ›› Issue (1): 10307-010307.doi: 10.1088/1674-1056/ae29fe
Yu-Han Yan(严雨涵)2,†, Yan-Ping Tan(谭艳萍)1,†, Yan-Yan Lu(陆艳艳)1,á, Shao-Jie Xiong(熊少杰)1,§, and Zhe Sun(孙哲)1,¶
Yu-Han Yan(严雨涵)2,†, Yan-Ping Tan(谭艳萍)1,†, Yan-Yan Lu(陆艳艳)1,á, Shao-Jie Xiong(熊少杰)1,§, and Zhe Sun(孙哲)1,¶
摘要: We present a theoretical investigation of weak-value amplification (WVA) under decoherence, quantifying its metrological capabilities through the quantum Fisher information (QFI). By modeling decoherence via Kraus operators acting before and after the weak measurement interaction, we derive exact expressions for the QFI governing parameter estimation of a weak coupling strength. These analytical results reveal the fundamental limitation imposed by decoherence on the QFI achievable via WVA. From these results, the optimal post-selection state that maximizes the QFI can be derived for different noise environments. Through paradigmatic examples, including amplitude damping and depolarizing channels, we demonstrate a key distinction: the optimal post-selection evolves with the noise strength in the amplitude damping channel, but is fixed in the depolarizing channel. This work provides both theoretical insights and practical guidance for optimizing metrological schemes based on WVA in realistic decoherent environments.
中图分类号: (Foundations of quantum mechanics; measurement theory)