LAUSR

We use a recently developed fRG method (extendend Coupled-Ladder Approximation) to study the 0.7 analog in quantum point contacts, arising at the crossing of the first and second band at sufficiently high magnetic fields. We reproduce the main features of the experimentally observed magnetic field dependence of the conductance at the 0.7 analog, using a QPC model with two bands and short-range interactions. In particular, we reproduce the fact that this dependence is qualitatively different, depending on whether the analog is approached from higher or lower magnetic fields. We show that this effect can be explained qualitatively within a simple Hartree picture for the influence of the lowest electrons.