Quantum Non-Gaussian Photon Coincidences

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 analyze the robustness of the quantum non-Gaussian coincidences and compare it to the heralded quantum non-Gaussianity of single photons based on them.

Automated summary

Photon coincidences play a crucial role in quantum technologies by revealing nonlinear quantum processes in matter and certifying a new quality of photon sources. The criteria for quantum non-Gaussian two-photon coincidences reject states emerging from Gaussian parametric processes, which often limit applications in quantum technologies. Additionally, the robustness of quantum non-Gaussian coincidences is analyzed and compared to the heralded quantum non-Gaussianity of single photons.