Complete identification of nonclassicality of Gaussian states via intensity moments

TL;DR

This paper introduces an experimental method using intensity moments and local displacements to fully identify and quantify the nonclassicality of Gaussian states with simple linear detectors, enhancing practical quantum state analysis.

Contribution

The authors develop a new technique that enables complete and quantitative identification of nonclassicality in Gaussian states using only intensity measurements and local displacements.

Findings

Method effectively identifies nonclassicality in Gaussian states.

Technique quantifies the degree of nonclassicality.

Requires only linear intensity detectors and local displacements.

Abstract

We present an experimental method for complete identification of the nonclassicality of Gaussian states in the whole phase space. Our method relies on nonclassicality witnesses written in terms of measured integrated intensity moments up to the third order, provided that appropriate local coherent displacements are applied to the state under consideration. The introduced approach, thus, only requires linear detectors for measuring intensities of optical fields, that is very convenient and powerful from the experimental point of view. Additionally, we demonstrate that the proposed technique not only allows to completely identify the nonclassicality of the Gaussian states but also to quantify it.