CPM Seminar

Measurements of non-Gaussian shot noise in mesoscopic samples

Betrand Reulet

Yale University

We present the first measurements of the third moment of the voltage fluctuations in a conductor. This quantity characterizes the asymmetry of the fluctuations. The shot noise becomes asymmetric, and thus non-Gaussian, as soon as the time reversal symmetry is broken by a dc current. The measurement was performed on non-superconducting tunnel junctions as a function of voltage bias, for various temperatures and bandwidths up to 1GHz. The data demonstrate the significant effect of the electromagnetic environment of the sample. Part of the effect of the environment comes from external voltage modulating the sample's noise. We show how this phenomenon directly probes the inelastic times in a diffusive wire and present the first experimental evidences.