  Electronic Hanbury Brown Twiss correlations are discussed for geometries in
which transport is along adiabatically guided edge channels. We briefly discuss
partition noise experiments and discuss the effect of inelastic scattering and
dephasing on current correlations. We then consider a two-source Hanbury Brown
Twiss experiment which demonstrates strikingly that even in geometries without
an Aharonov-Bohm effect in the conductance matrix (second-order interference),
correlation functions can (due to fourth-order interference) be sensitive to a
flux. Interestingly we find that this fourth-order interference effect is
closely related to orbital entanglement. The entanglement can be detected via
violation of a Bell Inequality in this geometry even so particles emanate from
uncorrelated sources.
