Robust strategies for lossy quantum interferometry

TL;DR

This paper introduces a multiround quantum interferometry strategy that surpasses the shot noise limit and outperforms existing methods in sensitivity, even with photon loss, by using twice the precision of traditional approaches.

Contribution

A simple multiround approach that exceeds the shot noise limit and outperforms recent strategies under lossy conditions.

Findings

Achieves twice the sensitivity of conventional interferometry in noiseless scenarios.

Remains more precise than recent optimal strategies even with photon loss.

Provides a practical method for enhanced quantum measurement precision.

Abstract

We give a simple multiround strategy that permits to beat the shot noise limit when performing interferometric measurements even in the presence of loss. In terms of the average photon number employed, our procedure can achieve twice the sensitivity of conventional interferometric ones in the noiseless case. In addition, it is more precise than the (recently proposed) optimal two-mode strategy even in the presence of loss.