Precision quantum metrology and nonclassicality in linear and nonlinear detection schemes

TL;DR

This paper investigates whether surpassing coherent states in quantum metrological resolution is inherently a nonclassical effect, revealing differences between linear and nonlinear detection schemes and proposing an experimental test based on quantum Fisher information.

Contribution

It demonstrates that nonclassicality is linked to linear detection schemes and introduces a simple experimental setup to test this relationship.

Findings

Nonclassicality is confirmed in linear detection schemes.

Nonclassicality is not necessary for nonlinear schemes.

A simple experimental test based on quantum Fisher information is proposed.

Abstract

We examine whether metrological resolution beyond coherent states is a nonclassical effect. We show that this is true for linear detection schemes but false for nonlinear schemes, and propose a very simple experimental setup to test it. We find a nonclassicality criterion derived from quantum Fisher information.