Spin Transport in Interacting Quantum Wires and Carbon Nanotubes

We present a general formulation of spin-dependent transport through a clean one-dimensional interacting quantum wire or carbon nanotube, connected to noncollinear ferromagnets via tunnel junctions. The low energy description of each junction is given by a conformally invariant boundary condition representing exchange coupling, in addition to a pair of electron tunneling operators. The effects of the exchange coupling are strongly enhanced by interactions, leading to a dramatic suppression of spin accumulation: a direct signature of spin-charge separation. Finally, backscattering induces nonequilibrium oscillations in the current-voltage relation.