  A novel mesoscopic electron spectrometer allows for the probing of relaxation
processes in quantum Hall edge channels. The device is composed of an emitter
quantum dot that injects energy-resolved electrons into the channel closest to
the sample edge, to be subsequently probed downstream by a detector quantum dot
of the same type. In addition to inelastic processes in the sample that stem
from interactions inside the region between the quantum dot energy filters
(inner region), anomalous signals are measured when the detector energy exceeds
the emitter energy. Considering finite range Coulomb interactions in the
sample, we find that energy exchange between electrons in the current inducing
source channel and the inner region, similar to Auger recombination processes,
is responsible for such anomalous currents. In addition, our perturbative
treatment of interactions shows that electrons emitted from the source, which
dissipate energy to the inner region before entering the detector, contribute
to the current most strongly when emitter-detector energies are comparable.
Charge transfer in which the emitted electron is exchanged for a charge carrier
from the Fermi sea, on the other hand, preferentially occurs close to the Fermi
level.
