Standard weak measurement (SWM) has been proved to be a useful ingredient for measuring small longitudinal phase shifts. [Phys. Rev. Lett. 111, 033604 (2013)]. In this letter, we show that with specfic pre-coupling and postselection, destructive interference can be observed for the two conjugated variables, i.e. time and frequency, of the meter state. Using a broad band source, this conjugated destructive interference (CDI) can be observed in a regime approximately 1 attosecond, while the related spectral shift reaches hundreds of THz. This extreme sensitivity can be used to detect tiny longitudinal phase perturbation. Combined with a frequency-domain analysis, conjugated destructive interference weak measurement (CDIWM) is proved to outperform SWM by two orders of magnitude.
@article{arxiv.1605.09536,
title = {Strengthen Weak Measurement with Conjugated Destructive Interference},
author = {Zi-Huai Zhang and Geng Chen and Xiao-Ye Xu and Jian-Shun Tang and Wen-Hao Zhang and Yong-Jian Han and Chuan-Feng Li and Guang-Can Guo},
journal= {arXiv preprint arXiv:1605.09536},
year = {2016}
}