Quantum transport in two-channel fractional quantum Hall edges

We study the effect of backward scatterings in the tunneling at a point contact between the edges of second-level hierarchical fractional quantum Hall states. A universal scaling dimension of the tunneling conductance is obtained only when both of the edge channels propagate in the same direction, It is shown that the quasiparticle-tunneling picture and the electron-tunneling picture give different scaling behaviors of the conductances, which indicates the existence of a crossover between the two pictures. When the direction of two edge channels are opposite, e.g., in the case of MacDonald's edge construction for the nu = 2/3 state [Phys. Rev. Lett. 64, 220 (1990)], the phase diagram is divided into two domains giving a different temperature dependence of the conductance.