Universal Conductance and Non-Universal Noise in Fractional Helical Wires


  Eyal Cornfeld  ,  Eran Sela  
Tel Aviv University

Similar to clean quantum wires with adiabatic contacts, partially gapped quantum wires exhibit quantized conductance, independent of electron-electron interaction. We show that this quantization persists in more general cases breaking the chiral symmetry and results in universally quantized fractional conductance. We derive the excitation charge of particles tunnelling across the gap and find that these charges reflect interaction between the gapped and gapless sectors.