Speaker: Peter Rabl
Affiliation: Walther-Meißner-Institute & TUM
Date: Tuesday, 24 February 2026 at 12:00
Location: Online seminar
In this talk, I discuss the many-body physics of interacting waveguide QED systems, where photons in a coupled-cavity array are strongly coupled to atomic impurities and interact via local Kerr nonlinearities. After introducing the model and its relevance to nanophotonic crystals, circuit QED lattices, and ultracold atomic systems, I briefly review the striking consequences that additional photon-photon interactions can have on the collective emission dynamics of atomic emitters. I then focus on the ground-state properties of this system, which are governed by the competition between attractive Jaynes-Cummings-mediated binding and intrinsic photon-photon repulsion. This interplay drives the formation of localized few-photon bound states and results in a rich phase diagram featuring Mott-like insulating states as well as superfluid phases characterized by long-range correlations mediated by photons detached from impurity sites.