Bose-Einstein condensation at a helium surface.
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.
Draeger
E W
EW
Department of Physics and National Center for Supercomputing Applications, University of Illinois-Urbana-Champaign, Urbana, Illinois 61801, USA.
Ceperley
D M
DM