  Motivated by the presence of various charge inhomogeneities in strongly
correlated systems of coupled ladders, a model of spatially separated bosonic
and fermionic degrees of freedom is numerically studied. In this model, bosonic
chains are connected to fermionic chains by two types of generalized Andreev
couplings. It is shown that for both types of couplings the long-distance
pairing correlations are enhanced. Near quarter filling, this effect is much
larger for the splitting of a pair in electrons which go to the two neighboring
fermionic chains than for a pair hopping process. It is argued that the pairing
enhancement is a result of the nearest neighbor Coulomb repulsion which tunes
the competition between pairing and charge ordering.
