Faithful hierarchy of genuine $n$-photon quantum non-Gaussian light

TL;DR

This paper introduces and experimentally verifies a hierarchy for identifying genuine n-photon quantum non-Gaussian light, providing a loss-tolerant diagnostic tool for advanced nonclassical states in quantum technology.

Contribution

The paper proposes a new hierarchy for genuine n-photon quantum non-Gaussian light and demonstrates its experimental verification, including the first conclusive witness of 3-photon quantum non-Gaussian light.

Findings

Successfully witnessed 3-photon quantum non-Gaussian light experimentally

Demonstrated the hierarchy's applicability to real quantum states

Provided a loss-tolerant diagnostic method for non-Gaussian quantum light

Abstract

Light is an essential tool for connections between quantum devices and for diagnostic of processes in quantum technology. Both applications deal with advanced nonclassical states beyond Gaussian coherent and squeezed states. Current development requires a loss-tolerant diagnostic of such nonclassical aspects. We propose and experimentally verify a faithful hierarchy of genuine $n$-photon quantum non-Gaussian light. We conclusively witnessed 3-photon quantum non-Gaussian light in the experiment. Measured data demonstrates a direct applicability of the hierarchy for a large class of real states.