Generating non-Gaussian states using collisions between Rydberg   polaritons
  We investigate theoretically the deterministic generation of quantum states with negative Wigner functions, by using giant non-linearities due to collisional interactions between Rydberg polaritons. The state resulting from the polariton interactions may be transferred with high fidelity into a photonic state, which can be analyzed using homodyne detection followed by quantum tomography. Besides generating highly non-classical states of the light, this method can also provide a very sensitive probe for the physics of the collisions involving Rydberg states. 
Jovica Stanojevic, Valentina Parigi, Erwan Bimbard, Alexei   Ourjoumtsev, Pierre Pillet and Philippe Grangier
quant-ph physics.atom-ph