Finite frequency noise in a quantum point contact between helical edge   states
  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. 
J.-R. Souquet and P. Simon
cond-mat.mes-hall