Conductance renormalization and conductivity in quantum wires with multiple subbands

Using a Tomonaga–Luttinger model, we studied the conductance renormalization and conductivity of a quantum wire with multiple subbands. As in a single-band system, the conductance of a quantum wire with an arbitrary number of subbands is not renormalized by the electron–electron interaction. For a dirty Tomonaga–Luttinger model with multiple subbands, we found that inter-subband interaction enhances the conductivity, which is contrary to that expected from the intra-subband repulsive interaction, and that the conductivity increases with increasing number of subbands.