Non-Gaussian state generation certified using the EPR-steering inequality

TL;DR

This paper demonstrates that the EPR-steering inequality can serve as a practical witness for generating pure bipartite non-Gaussian states, with experimental evidence from SPDC processes highlighting intrinsic non-Gaussianity.

Contribution

It introduces a new method using EPR-steering inequality to certify non-Gaussian state generation in continuous-variable quantum systems.

Findings

EPR-steering inequality can witness non-Gaussianity in CV states

Experimental observation of non-Gaussianity in SPDC-generated two-photon states

Non-Gaussianity arises from phase-matching conditions in SPDC

Abstract

Due to practical reasons, experimental and theoretical continuous-variable (CV) quantum information (QI) has been heavily based on Gaussian states. Nevertheless, many CV-QI protocols require the use of non-Gaussian states and operations. Here, we show that the Einstein-Podolsky-Rosen steering inequality can be used to obtain a practical witness for the generation of pure bipartite non-Gaussian states. While the scenario require pure states, we show its broad relevance by reporting the experimental observation of the non-Gaussianity of the CV two-photon state generated in the process of spontaneous parametric down-conversion (SPDC). The observed non-Gaussianity is due only to the intrinsic phase-matching conditions of SPDC