  We study the quality of state and entanglement transmission through quantum
channels described by spin chains varying both the system parameters and the
initial state of the channel. We consider a vast class of one-dimensional
many-body models which contains some of the most relevant experimental
realizations of quantum data-buses. In particular, we consider spin-1/2 XY and
XXZ model with open boundary conditions. Our results show a significant
difference between free-fermionic (non-interacting) systems (XY) and
interacting ones (XXZ), where in the former case initialization can be
exploited for improving the entanglement distribution, while in the latter case
it also determines the quality of state transmission. In fact, we find that in
non interacting systems the exchange with fermions in the initial state of the
chain always has a destructive effect, and we prove that it can be completely
removed in the isotropic XX model by initializing the chain in a ferromagnetic
state. On the other hand, in interacting systems constructive effects can arise
by scattering between hopping fermions and a proper initialization procedure.
Remarkably our results are the first example in which state and entanglement
transmission show maxima at different points as the interactions and
initializations of spin chain channels are varied.
