Paper on 3-photon correlations mediated by a Rydberg superatom

Nontrivial three-photon correlations can be imprinted onto initially uncorrelated photons through an interaction with a single Rydberg superatom, something the SDU group has recently observed experimentally:

https://doi.org/10.1103/PhysRevLett.121.103601

By exploiting the Rydberg blockade mechanism, they turn a cold atomic cloud into a single effective emitter with collectively enhanced coupling to a focused photonic mode which gives rise to clear signatures in the connected part of the three-body correlation function of the outgoing photons. The results are in good agreement with a quantitative model for a single, strongly coupled Rydberg superatom. Furthermore, they developed an idealized but exactly solvable model of a single two-level system coupled to a photonic mode, which allows for an interpretation of the experimental observations in terms of bound states and scattering states.