We consider the conductance of a quantum tube connected to a metallic
contact. The number of angular momentum states that the tube can support
depends on the strength of the radial confinement. We calculate the
transmission coefficients which yield the conductance via the Landauer formula.
We relate our results to armchair carbon nanotubes embedded in a metal. For Al
and Au contacts and tubes with a realistic radial confinement we find that the
transmission can be close to unity corresponding to a contact resistance close
to h/2e^2 per band at the Fermi level in the carbon nanotube.Comment: 13 pages including 5 figures. Accepted for publication in
Superlattices and Microstructures. (stylefile included
