  We propose to realize a p-wave superfluid using bosons mixed with a single
species of fermions in a deep optical lattice. We analyze with a
self-consistent method its excitation spectrum in presence of a vortex, and we
point out the range of interaction strengths in which the zero-energy mode with
topological character exists on a finite optical lattice. Lattice effects are
strongest close to fermionic half-filling: here the linearity of the low-lying
spectrum is lost, and a new class of extended zero-energy modes with
checkerboard structure and d-wave symmetry appears.
