  The spectral weight ${\rm A({\bf p},\omega)}$ of the two dimensional ${\rm
t-J}$ and Hubbard models has been calculated using exact diagonalization and
quantum Monte Carlo techniques, at several densities ${\rm 1.0 \leq \langle n
\rangle \leq 0.5}$. The photoemission $(\omega < 0)$ region contains two
dominant distinct features, namely a low-energy quasiparticle peak with
bandwidth of order J, and a broad valence band peak at energies of order t.
This behavior $persists$ away from half-filling, as long as the
antiferromagnetic (AF) correlations are robust. The results give support to
theories of the copper oxide materials based on the behavior of holes in
antiferromagnets, and it also provides theoretical guidance for the
interpretation of experimental photoemission data for the cuprates.

Condensed Matter