Witnessing the degree of nonclassicality of light

TL;DR

This paper presents a practical method to quantify the nonclassicality of light based on quantum superposition, enabling experimental certification of the degree of nonclassicality in various quantum states.

Contribution

It introduces a novel, experimentally feasible measure of nonclassicality and provides a systematic way to test and certify this measure for different quantum states.

Findings

Method successfully applied to squeezed states

Allows certification of nonclassicality in single- and multimode fields

Provides optimal tests and numerical implementation

Abstract

We introduce an experimentally accessible method to measure a unique degree of nonclassicality, based on the quantum superposition principle, for arbitrary quantum states. We formulate witnesses and test a given state for any particular value of this measure. The construction of optimal tests is presented as well as the general numerical implementation. We apply this approach on examples such as squeezed states, and we show how to formulate conditions to certify a particular degree of nonclassicality for single- and multimode radiation fields.