  We study the quantum dynamics of ballistic electrons in rotating carbon
nanotubes in the presence of a uniform magnetic field. When the field is
parallel to the nanotube axis, the rotation-induced electric field brings about
the spin-orbit interaction which, together with the kinetic, inertial, and
Zeeman terms, compose the Schr\"odinger-Pauli Hamiltonian of the system. Full
diagonalization of this Hamiltonian yields the eigenstates and eigenenergies
leading to the calculation of the charge and spin currents. Our main result is
the demonstration that, by suitably combining the applied magnetic field
intensity and rotation speed, one can tune one of the currents to zero while
keeping the other one finite, giving rise to a spin current generator.
