Quantum non-Gaussian Photon Coincidences

TL;DR

This paper introduces criteria to certify quantum non-Gaussian two-photon coincidences, enhancing the quality assessment of photon sources crucial for quantum technologies, and analyzes their robustness compared to single-photon non-Gaussianity.

Contribution

It develops broadly applicable criteria for quantum non-Gaussian photon coincidences that distinguish them from Gaussian processes, improving source certification.

Findings

Criteria effectively reject Gaussian-origin states.

Quantum non-Gaussian coincidences are robust against noise.

Comparison shows advantages over heralded single-photon non-Gaussianity.

Abstract

Photon coincidences represent an important resource for quantum technologies. They expose nonlinear quantum processes in matter and are essential for sources of entanglement. We derive broadly applicable criteria for quantum non-Gaussian two-photon coincidences that certify a new quality of photon sources. The criteria reject states emerging from Gaussian parametric processes, which often limit applications in quantum technologies. We also analyse the robustness of the quantum non-Gaussian coincidences and compare with the heralded quantum non-Gaussianity of single-photons based on them.