We study the transport of atoms across a localized Bose-Einstein condensate
in a one-dimensional optical lattice. For atoms scattering off the condensate
we predict total reflection as well as full transmission for certain parameter
values on the basis of an exactly solvable model. The findings of analytical
and numerical calculations are interpreted by a tunable Fano-like resonance and
may lead to interesting applications for blocking and filtering atom beams.Comment: 4 pages, 4 figures (fig4 was resized for arXiv