Precursors of a Mott insulator in modulated quantum wires

We investigate the transport of interacting electrons through single-mode quantum wires whose parameters are periodically modulated on the scale of the electronic Fermi wavelength. The Umklapp scattering and backscattering of electrons can be described in terms of nonuniform quantum sine-Gordon-like models that also incorporate the effects of electronic reservoirs (electrodes) adiabatically coupled to the wire. We concentrate on weak Umklapp scattering and analyze the precursors of the Mott transition. At half-filling the temperature dependence of the extra resistance ΔR=R-π/e² of a modulated quantum wire of length L changes from the interaction-dependent ``bulk'' power-law ΔR∝T^4K_ρ-3 at high temperatures (Tv_ρ/L) to the universal ΔR∝T² behavior at low temperatures (Tv_ρ/L). Away from half-filling the ``bulk'' results are qualitatively incorrect even at high temperatures v_ρ/LTT* despite the fact that the electron coherence in the wire is absent in this regime.