Coulomb drag between quantum wires with different electron densities

We study the way the backscattering electron-electron interaction generates Coulomb drag between quantum wires with different densities. At low temperature T the system can undergo a commensurate-incommensurate transition as the potential difference \W\ between the two wires passes a critical value Delta, and this transition is reflected in a marked change in the dependence of drag resistivity on W and T. At high temperature a density difference between the wires suppresses Coulomb drag induced by backscattering, and we use the Tomonaga-Luttinger model to study this suppression in detail.