  Shot noise measurements are widely used for the characterization of
nonequilibrium configurations in electronic conductors. The recently introduced
quantum tomography approach was implemented for the studies of electronic
wavefunctions of few-electron excitations created by periodic voltage pulses in
phase-coherent ballistic conductors based on the high-quality GaAs
two-dimensional electron gas. Still relying on the manifestation of Fermi
correlations in noise, we focus on the simpler and more general approach
beneficial for the local measurements of energy distribution (ED) in electronic
systems with arbitrary excitations with well-defined energies and random
phases. Using biased diffusive metallic wire as a testbed, we demonstrate the
power of this approach and extract the well-known double-step ED from the shot
noise of a weakly coupled tunnel junction. Our experiment paves the way for the
local measurements of generic nonequilibrium configurations applicable to
virtually any conductor.

Mesoscale and Nanoscale Physics