  Recent experiments [M. Yamamoto et al., Nature Nanotechnology 7, 247 (2012)]
used the transport of electrons through an Aharonov-Bohm interferometer and two
coupled channels (at both ends of the interferometer) to demonstrate a
manipulable flying qubit. Results included in-phase and anti-phase
Aharonov-Bohm (AB) oscillations of the two outgoing currents as a function of
the magnetic flux, for strong and weak inter-channel coupling, respectively.
Here we present new experimental results for a three terminal interferometer,
with a tunnel coupling between the two outgoing wires. We show that in some
limits, this system is an even simpler realization of the "two-slit"
experiment. We also present a simple tight- binding theoretical model which
imitates the experimental setup. For weak inter-channel coupling, the AB
oscillations in the current which is reflected from the device are very small,
and therefore the oscillations in the two outgoing currents must cancel each
other, yielding the anti-phase behavior, independent of the length of the
coupling regime. For strong inter-channel coupling, whose range depends on the
asymmetry between the channels, and for a relatively long coupling distance,
all except two of the waves in the coupled channels become evanescent. For the
remaining running waves one has a very weak dependence of the ratio between the
currents in the two channels on the magnetic flux, implying that these currents
are in phase with each other.
