Moments of nonclassicality quasiprobabilities

TL;DR

This paper introduces a method to verify quantum nonclassicality using moments of nonclassicality quasiprobability distributions derived from experimental data, connecting them to established criteria for properties like squeezing.

Contribution

It develops a framework linking nonclassicality moments to normally-ordered moments, enabling direct verification of nonclassicality from experimental data.

Findings

Nonclassicality moments can be obtained from experimental data.

Verification criteria are formulated directly in terms of nonclassicality moments.

The approach converges to traditional criteria for squeezing and sub-Poissonian statistics.

Abstract

A method is introduced for the verification of nonclassicality in terms of moments of nonclassicality quasiprobability distributions. The latter are easily obtained from experimental data and will be denoted as nonclassicality moments. Their relation to normally-ordered moments is derived, which enables us to verify nonclassicality by using well established criteria. Alternatively, nonclassicality criteria are directly formulated in terms of nonclassicality moments. The latter converge in proper limits to the usually used criteria, as is illustrated for squeezing and sub-Poissonian photon statistics. Our theory also yields expectation values of any observable in terms of nonclassicality moments.