  New generation of Cooper pair splitters defined on hybrid nanostructures are
devices with high tunable coupling parameters. Transport measurements through
these devices revealed clear signatures of interference effects and motivated
us to introduce a new model, called the 3-sites model. These devices provide an
ideal playground to tune the Cooper pair splitting (CPS) efficency on demand,
and displays a rich variety of physical phenomena. In the present work we
analyze theoretically the conductance of the 3-sites model in the linear and
non-linear regimes and characterize the most representative features that arise
by the interplay of the different model parameters. In the linear regime we
find that the local processes typically exhibit Fano-shape resonances, while
the CPS contribution exhibits Lorentzian-shapes. Remarkably, we find that under
certain conditions, the transport is blocked by the presence of a dark state.
In the non-linear regime we established a hierarchy of the model parameters to
obtain the conditions for optimal efficency.
