  Nanotubes with proper thickness, size and texture make ultra-efficient sinks
for the quantum particles traveling into specific background media. Several
optimal semiconducting cylindrical layers are reported to achieve enhancement
in the trapping of matter waves by 2-3 orders of magnitude. The identified
shells can be used as pieces in quantum devices that involve the focusing of
incident beams from charge pumps and superconducting capacitors to radiation
pattern controllers and matter-wave lenses.
