title: Cavity quantum electrodynamics with many-body states of a two-dimensional electron gas.
abstract: Light-matter interaction has played a central role in understanding as well as engineering new states of matter. Reversible coupling of excitons and photons enabled groundbreaking results in condensation and superfluidity of nonequilibrium quasiparticles with a photonic component. We investigated such cavity-polaritons in the presence of a high-mobility two-dimensional electron gas, exhibiting strongly correlated phases. When the cavity was on resonance with the Fermi level, we observed previously unknown many-body physics associated with a dynamical hole-scattering potential. In finite magnetic fields, polaritons show distinct signatures of integer and fractional quantum Hall ground states. Our results lay the groundwork for probing nonequilibrium dynamics of quantum Hall states and exploiting the electron density dependence of polariton splitting so as to obtain ultrastrong optical nonlinearities.
authors.affiliation: Institute of Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zurich, 8093 Zurich, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Smolka
authors.affiliation: Institute of Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zurich, 8093 Zurich, Switzerland. Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Wolf
authors.initials: W
authors.lastname: Wuester
authors.affiliation: Institute of Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zurich, 8093 Zurich, Switzerland.
authors.forename: Florian
authors.initials: F
authors.lastname: Haupt
authors.affiliation: Institute of Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zurich, 8093 Zurich, Switzerland. Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Faelt
authors.affiliation: Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Werner
authors.initials: W
authors.lastname: Wegscheider
authors.affiliation: Institute of Quantum Electronics, Eidgenössische Technische Hochschule (ETH) Zurich, 8093 Zurich, Switzerland. imamoglu@phys.ethz.ch.
authors.forename: Ataç
authors.initials: A
authors.lastname: Imamoglu