  Split-gate constrictions can be used to produce controllable scattering in a
fractional quantum Hall state and constitute a very versatile model system for
the investigation of non-Fermi physics in edge states. Controllable inter-edge
tunneling can be achieved by tuning the constriction parameters and its
out-of-equilibrium behavior can be explored as well. Here we review our results
of tunneling non-linearities at a split-gate constriction in a wide range of
temperatures and inter-edge coupling. The results are compared to available
theoretical predictions of tunneling characteristics between Luttinger liquids.
We show how partial agreement with these theoretical models is obtained in
selected ranges of temperatures and inter-edge coupling, while striking
deviations are obtained especially in the low-coupling, low-temperature
regimes.
