Strengthen Weak Measurement with Conjugated Destructive Interference

TL;DR

This paper introduces conjugated destructive interference weak measurement (CDIWM), a novel technique that significantly enhances sensitivity for detecting tiny phase shifts by exploiting destructive interference in conjugated variables, outperforming standard weak measurement.

Contribution

The paper demonstrates a new weak measurement method utilizing conjugated destructive interference to achieve higher sensitivity in phase shift detection.

Findings

CDIWM outperforms standard weak measurement by two orders of magnitude.

Extreme sensitivity allows detection of phase perturbations at the attosecond scale.

Spectral shifts of hundreds of THz are observed with broad band sources.

Abstract

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.