title: Rydberg polaritons in a cavity: a superradiant solid.
abstract: We study an optical cavity coupled to a lattice of Rydberg atoms, which can be represented by a generalized Dicke model. We show that the competition between the atom-atom interaction and atom-light coupling induces a rich phase diagram. A novel superradiant solid (SRS) phase is found, where both the superradiance and crystalline orders coexist. Different from the normal second order superradiance transition, here both the solid-1/2 and SRS to SR phase transitions are first order. These results are confirmed by large scale quantum Monte Carlo simulations.
authors.affiliation: Physics Department and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Zhang
authors.forename: Qing
authors.initials: Q
authors.lastname: Sun
authors.forename: Yu-Chuan
authors.initials: YC
authors.lastname: Wen
authors.forename: Wu-Ming
authors.initials: WM
authors.lastname: Liu
authors.forename: Sebastian
authors.initials: S
authors.lastname: Eggert
authors.forename: An-Chun
authors.initials: AC
authors.lastname: Ji