Interacting quantum wires: A possible explanation for the 0.7 anomalous conductance

We investigate an effective one-dimensional conducting channel considering both the contact umklapp and the Coulomb electron–electron interaction. We show that, at low electronic density, the proximity to the Wigner crystal reproduces the anomaly in conductance at 0.7G00.7G0. The crucial ingredient of our theory is the fact that the gate voltage acts as a bias controlling the intensity of the umklapp term. At large gate voltages, the umklapp vanishes and we obtain a conducting quantum wire with a perfect conductance. At low gate voltages, the Wigner crystal is pinned by the umklapp term, giving rise to an insulating behavior with vanishing conductance. This crossover pattern has a transition point which can be identified with the anomalous conductance around 0.7G00.7G0. This picture is obtained within the framework of a renormalization group calculation. The conductance static regime is achieved by taking first the limit of finite length and then the limit of zero frequency.