  We investigate the properties of conduction electrons in single-walled
armchair carbon nanotubes in the presence of mutually orthogonal electric and
magnetic fields transverse to the tube's axis. We find that the fields give
rise to an asymmetric dispersion in the right- and left-moving electrons along
the tube as well as a band-dependent interaction. We predict that such a
nanotube system would exhibit spin-band-charge separation and a band-dependant
tunneling density of states. We show that in the quantum dot limit, the fields
serve to completely tune the quantum states of electrons added to the nanotube.
For each of the predicted effects, we provide examples and estimates that are
relevant to experiment.
