title: Supermode-density-wave-polariton condensation with a Bose-Einstein condensate in a multimode cavity.
abstract: Phase transitions, where observable properties of a many-body system change discontinuously, can occur in both open and closed systems. By placing cold atoms in optical cavities and inducing strong coupling between light and excitations of the atoms, one can experimentally study phase transitions of open quantum systems. Here we observe and study a non-equilibrium phase transition, the condensation of supermode-density-wave polaritons. These polaritons are formed from a superposition of cavity photon eigenmodes (a supermode), coupled to atomic density waves of a quantum gas. As the cavity supports multiple photon spatial modes and because the light-matter coupling can be comparable to the energy splitting of these modes, the composition of the supermode polariton is changed by the light-matter coupling on condensation. By demonstrating the ability to observe and understand density-wave-polariton condensation in the few-mode-degenerate cavity regime, our results show the potential to study similar questions in fully multimode cavities.
authors.affiliation: Department of Applied Physics, Stanford University, MC 305, Stanford, California 94305, USA.|E.L. Ginzton Laboratory, Stanford University, MC 305, Stanford, California 94305-4088, USA.
authors.forename: Alicia J
authors.initials: AJ
authors.lastname: Kollár
authors.affiliation: Department of Applied Physics, Stanford University, MC 305, Stanford, California 94305, USA.|E.L. Ginzton Laboratory, Stanford University, MC 305, Stanford, California 94305-4088, USA.
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Papageorge
authors.affiliation: E.L. Ginzton Laboratory, Stanford University, MC 305, Stanford, California 94305-4088, USA.
authors.forename: Varun D
authors.initials: VD
authors.lastname: Vaidya
authors.affiliation: E.L. Ginzton Laboratory, Stanford University, MC 305, Stanford, California 94305-4088, USA.|Department of Physics, Stanford University, Stanford, MC 305, California 94305, USA.
authors.forename: Yudan
authors.initials: Y
authors.lastname: Guo
authors.affiliation: SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.
authors.forename: Jonathan
authors.identifier: 0000-0002-4283-552X
authors.initials: J
authors.lastname: Keeling
authors.affiliation: Department of Applied Physics, Stanford University, MC 305, Stanford, California 94305, USA.|E.L. Ginzton Laboratory, Stanford University, MC 305, Stanford, California 94305-4088, USA.|Department of Physics, Stanford University, Stanford, MC 305, California 94305, USA.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Lev