Depletion of superfluid fraction in the quasi-two-dimensional Bose gas
Phys. Rev. B 46, 5463 – Published 1 September, 1992
DOI: https://doi.org/10.1103/PhysRevB.46.5463
Abstract
A theory is presented for the depletion of superfluid density in a low-temperature Bose gas adsorbed on a surface. Longitudinal excitations are treated in a Bogoliubov type of approximation. Transverse modes are found to contribute significantly if the excitation energy of adatoms normal to the surface is small.