Pre- and post-selected measurements with coupling-strength-dependent modulation
Abstract
Pre- and post-selected (PPS) measurement, especially the weak PPS measurement, is a useful protocol for amplifying small physical parameters. However, it is difficult to retain both the attainable highest measurement sensitivity and precision with the increase of the parameter to be measured. Here, a modulated PPS measurement scheme based on coupling-strength-dependent modulation is presented with the highest sensitivity and precision retained for an arbitrary coupling strength. This idea is demonstrated by comparing the modulated PPS measurement scheme with standard PPS measurementv scheme, respectively, in the cases of balanced pointer and unbalanced pointer. By using the Fisher information metric, we derive the optimal pre- and post-selected states, as well as the optimal coupling-strength-dependent modulation without any restriction on the coupling strength. We also give the specific strategy of performing the modulated PPS measurement scheme, which may promote practical application of this scheme in precision metrology.
Cite
@article{arxiv.1805.01893,
title = {Pre- and post-selected measurements with coupling-strength-dependent modulation},
author = {Zhaoxue Li and Jiangdong Qiu and Xiaodong Qiu and Linguo Xie and Lan Luo and Xiong Liu and Yu He and Qi Wang and Zhiyou Zhang and JingLei Du},
journal= {arXiv preprint arXiv:1805.01893},
year = {2019}
}