Quantum nonlinear optics in Rydberg systems
Prof. Dr. Thomas Pohl (Department of Physics and Astronomy, Aarhus University, Denmark)

The combination of electromagnetically induced transparency (EIT) and strongly interacting atomic states in optical media has opened up new routes towards achieving few-photon optical nonlinearities. While EIT provides strong light-matter coupling under low-loss conditions, the interactions between such Rydberg states can be used to generate nonlinearities that are large enough to operate on the level of single photons.

Such synthetic interactions promise few-photon applications and exotic many-body physics, emerging from the interplay of coherent driving, quantum light propagation, strong atomic interactions and dissipative photon scattering. This talk will present basic concepts underlying this approach and discuss simple examples that afford an intuitive understanding. Placing particular emphasis on many-body decoherence processes we will identify challenges but also new opportunities for generating and manipulating nonclassical states of light. Finally, we will consider new ideas beyond traditional Rydberg-EIT approaches as well as new platforms beyond ultracold atomic ensembles.