# Building materials from light: Photonic Landau levels and Rydberg-mediated interactions

**Speaker:**Ariel Sommer, MIT

**When:**January 23, 2017 (Mon), 03:30PM to 04:30PM (add to my calendar)

**Location:**SCI 328

*This event is part of the Biophysics/Condensed Matter Seminar Series. *

Advances in the control of light propagation and photon-photon interactions have lead to a new notion of photonic materials -- states of light that resemble material systems. I will describe our experimental approach to photonic materials, in which we use a degenerate non-planar optical resonator to realize a two-dimensional photon gas with an effective magnetic field. We observe photonic Landau levels, indicating a strong effective magnetic field, and a singularity of spatial curvature arising from the effectively conical geometry of our photon gas. Spatial curvature provides a novel probe of quantum Hall states, allowing us to make the first experimental measurement of the mean orbital spin, which characterizes topological phases. To realize photon-photon interactions, we demonstrate hybridization of photons in an optical resonator with atomic Rydberg excitations. Future work will aim to realize strongly correlated photonic fractional quantum Hall states by combining strong effective gauge fields with photon-photon interactions.