We investigate the finite frequency (f.f.) noise properties of edge states in the quantum Hall regime. We consider the measurement scheme of a resonant detector coupled to a quantum point contact in the weak-backscattering limit. A detailed analysis
of the difference between the measured noise, due to the presence of the resonant detector, and the symmetrized f.f. noise is presented. We discuss both the Laughlin and Jain sequences, studying the tunnelling excitations in these hierarchical models. We argue that the measured noise can better distinguish between the different excitations in the tunnelling process with respect to the symmetrized f.f. counterpart in an experimentally relevant range of parameters. Finally, we illustrate the effect of the detector temperature on the sensibility of this measure.
We propose a general mechanism for renormalization of the tunneling exponents in edge states of the fractional quantum Hall effect. Mutual effects of the coupling with out-of-equilibrium 1/f noise and dissipation are considered both for the Laughlin
sequence and for composite co- and counter-propagating edge states with Abelian or non-Abelian statistics. For states with counter-propagating modes we demonstrate the robustness of the proposed mechanism in the so called disorder-dominated phase. Prototypes of these states, such as u=2/3 and u=5/2, are discussed in detail and the rich phenomenology induced by the presence of a noisy environment is presented. The proposed mechanism justifies the strong renormalizations reported in many experimental observations carried out at low temperatures. We show how environmental effects could affect the relevance of the tunneling excitations, leading to important implications in particular for the u=5/2 case.
We present an explanation for the anomalous behavior in tunneling conductance and noise through a point contact between edge states in the Jain series $ u=p/(2np+1)$, for extremely weak-backscattering and low temperatures [Y.C. Chung, M. Heiblum, and
V. Umansky, Phys. Rev. Lett. {bf{91}}, 216804 (2003)]. We consider edge states with neutral modes propagating at finite velocity, and we show that the activation of their dynamics causes the unexpected change in the temperature power-law of the conductance. Even more importantly, we demonstrate that multiple-quasiparticles tunneling at low energies becomes the most relevant process. This result will be used to explain the experimental data on current noise where tunneling particles have a charge that can reach $p$ times the single quasiparticle charge. In this paper we analyze the conductance and the shot noise to substantiate quantitatively the proposed scenario.
