Finite frequency noise in a quantum point contact between helical edge states

TL;DR

This paper investigates how finite frequency noise measurements can distinguish between different quasiparticle processes in helical edge states of quantum spin Hall systems, providing a new method to characterize their helical nature.

Contribution

It introduces a novel approach using finite frequency noise to differentiate one-particle and two-particle processes in helical edge states, enhancing understanding of their non-equilibrium properties.

Findings

Finite frequency noise can distinguish quasiparticle processes.

The method discriminates between tunneling and backscattering regimes.

Provides a tool for characterizing helical edge states.

Abstract

We propose and analyze the non-equilibrium finite frequency current-current correlations as a mean to characterize the helical nature of the edge states in a quantum spin hall geometry. We show that the finite frequency noise enables to unambiguously discriminate between the one-particle and the two-particles processes occurring in the helical liquid for both tunneling or weak-backscattering regimes.