Spin-charge separation, tunneling, and spin transport in one-dimensional metals

Electron-electron interactions have strong effects on the low-energy excitations of a one-dimensional metal. Luttinger liquid theory, which is supposed to describe this situation, predicts, among other things, that an injected electron will split into separate charge and spin excitations, which propagate at different velocities. We shall review some experiments and theoretical analyses where spin-charge separation can have manifest consequences, including discussion of the spin-incoherent regime, which can occur in low-density electron systems, when the temperature is low compared to the energy scale for charge excitations, but larger than the spin-exchange energy for neighboring electrons.