We study an interacting ensemble of instantons at finite baryon chemical
potential. We emphasize the importance of fermionic zero modes and calculate
the fermion induced interaction between instantons at non-zero chemical
potential. We show that unquenched simulations of the instanton ensemble are
feasible in two regimes, for sufficiently small and for very large chemical
potential. At very large chemical potential chiral symmetry is restored and the
instanton ensemble is dominated by strongly correlated chain-like
configurations.Comment: 37 pages, 10 figures, uses revtex, revised version (minor corrections
and expanded dicussion