title: Power-law decay of the spatial correlation function in exciton-polariton condensates.
abstract: We create a large exciton-polariton condensate and employ a Michelson interferometer setup to characterize the short- and long-distance behavior of the first order spatial correlation function. Our experimental results show distinct features of both the two-dimensional and nonequilibrium characters of the condensate. We find that the gaussian short-distance decay is followed by a power-law decay at longer distances, as expected for a two-dimensional condensate. The exponent of the power law is measured in the range 0.9-1.2, larger than is possible in equilibrium. We compare the experimental results to a theoretical model to understand the features required to observe a power law and to clarify the influence of external noise on spatial coherence in nonequilibrium phase transitions. Our results indicate that Berezinskii-Kosterlitz-Thouless-like phase order survives in open-dissipative systems.
authors.affiliation: E. L. Ginzton Laboratory, Stanford University, Stanford, CA 94305, USA. georgios.roumpos@jila.colorado.edu
authors.forename: Georgios
authors.initials: G
authors.lastname: Roumpos
authors.forename: Michael
authors.initials: M
authors.lastname: Lohse
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Nitsche
authors.forename: Jonathan
authors.initials: J
authors.lastname: Keeling
authors.forename: Marzena Hanna
authors.initials: MH
authors.lastname: Szymanska
authors.forename: Peter B
authors.initials: PB
authors.lastname: Littlewood
authors.forename: Andreas
authors.initials: A
authors.lastname: Löffler
authors.forename: Sven
authors.initials: S
authors.lastname: Höfling
authors.forename: Lukas
authors.initials: L
authors.lastname: Worschech
authors.forename: Alfred
authors.initials: A
authors.lastname: Forchel
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yamamoto