Effect of inter-edge Coulomb interactions on transport through a point contact in a \nu = 5/2 quantum Hall state

We study transport across a point contact separating two line junctions in a \nu = 5/2 quantum Hall system. We analyze the effect of inter-edge Coulomb interactions between the chiral bosonic edge modes of the half-filled Landau level (assuming a Pfaffian wave function for the half-filled state) and of the two fully filled Landau levels. In the presence of inter-edge Coulomb interactions between all the six edges participating in the line junction, the stable fixed point corresponds to a point contact which is neither fully opaque nor fully transparent. Remarkably, this fixed point represents a situation where the half-filled level is fully transmitting, while the two filled levels are completely backscattered; hence the fixed point Hall conductance is given by G_H = {1/2} e^2/h. We predict the non-universal temperature power laws by which the system approaches the stable fixed point from the two unstable fixed points corresponding to the fully connected case (G_H = {5/2} e^2/h) and the fully disconnected case (G_H = 0).Comment: 6 pages, 3 figures; made several changes -- this is the published versio

Spectral noise for edge states at filling factor ν=5/2\nu=5/2

We present a detailed analysis of finite frequency noise for the $\nu=5/2$ fractional quantum Hall state in a quantum point contact geometry. The results are obtained within the Pfaffian and anti-Pfaffian models. We show that the behaviour of the coloured noise allows unambigously to discriminate among tunneling excitations with different charges. Optimal values of the external bias are found in order to emphasize the visibility of the noise peak associated with the tunneling of a 2-agglomerate, namely an excitation with charge double of the fundamental one. These correspond to the regime in which the bias is larger than the neutral modes cut-off frequency. The dependence on the temperature is also investigated in order to discriminate between the considered models.Comment: 14 pages, 4 figures. Submitted to New Journal of Phyisc