Conductance renormalization and conductivity of a multisubband Tomonaga-Luttinger model

We studied the conductance renormalization and conductivity of multisubband Tomonaga-Luttinger models with intersubband interactions. We found that, as in single-band systems, the conductance of a multisubband system with an arbitrary number of subbands is not renormalized due to interaction between electrons. We derived a formula for the conductivity in multisubband models. We applied it to a simplified case and found that intersubband interaction enhances the conductivity, which is contrary to the intrasubband repulsive interaction, and that the conductivity is further enhanced for a larger number of subbands.