  Entanglement can be generated by two electrons in a spin-zero state on a
semiconducting single-walled carbon nanotube. The two electrons, one weakly
bound in a shallow well in the conduction band, and the other injected into the
conduction band, are coupled by the Coulomb interaction. Both transmission and
entanglement are dependent on the well characteristics, which can be controlled
by a local gate, and on the kinetic energy of the injected electron. Regimes
with different degrees of electron correlation exhibit full or partial
entanglement. In the latter case, the maximum entanglement can be estimated as
a function of width and separation of a pair of singlet-triplet resonances.
