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

Abstract

We propose and analyze the nonequilibrium 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 one to unambiguously discriminate between the one-particle and the two-particle processes occurring in the helical liquid for both tunneling or weak-backscattering regimes.