  The two-nucleon spectral function in nuclear matter is studied using
Correlated Basis Function perturbation theory, including central and tensor
correlations produceded by a realistic hamiltonian. The factorization property
of the two-nucleon momentum distribution into the product of the two single
nucleon distributions shows up in an analogous property of the spectral
function. The correlated model yields a two-hole contribution quenched whith
respect to Fermi gas model, while the peaks acquire a quasiparticle width that
vanishes as the two momenta approach $k_F$. In addition, three-hole
one-particle and more complicated intermediate states give rise to a
background, spread out in energy and absent in the uncorrelated models. The
possible connections with one- and two-nucleon emission processes are briefly
discussed.
