title: Bose-Einstein condensation at a helium surface.
abstract: A path integral Monte Carlo method was used to calculate the Bose-Einstein condensate fraction at the surface of a helium film at T = 0.77 K, as a function of density. Moving from the center of the slab to the surface, the condensate fraction was found to initially increase with decreasing density to a maximum value of 0.9 before decreasing. Long wavelength density correlations were observed in the static structure factor at the surface of the slab. Finally, a surface dispersion relation was calculated from imaginary-time density-density correlations.
authors.affiliation: Department of Physics and National Center for Supercomputing Applications, University of Illinois-Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: E W
authors.initials: EW
authors.lastname: Draeger
authors.forename: D M
authors.initials: DM
authors.lastname: Ceperley