  Deep multi-color galaxy surveys with photometric redshifts will provide a
large number of two-point correlation observables: galaxy-galaxy angular
correlations, galaxy-shear cross correlations, and shear-shear correlations
between all redshifts. These observables can potentially enable a joint
determination of the dark energy dependent evolution of the dark matter and
distances as well as the relationship between galaxies and dark matter halos.
With recent CMB determinations of the initial power spectrum, a measurement of
the mass clustering at even a_single_ redshift will constrain a well-specified
combination of dark energy parameters in a flat universe; we provide convenient
fitting formulae for such studies. The combination of galaxy-shear and
galaxy-galaxy correlations can determine this amplitude at_multiple_ redshifts.
We illustrate this ability in a description of the galaxy clustering with 5
free functions of redshift which can be fitted from the data. The galaxy
modeling is based on a mapping onto halos of the same abundance that models a
flux-limited selection. In this context, a 4000 deg2 galaxy-lensing survey can
achieve a_statistical_ precision of sigma(Omega_DE)=0.005 for the dark energy
density, sigma(w_DE)=0.02 and sigma(w_a)=0.17 for its equation of state and
evolution, evaluated at dark energy matter equality z~0.4, as well as
constraints on the 5 halo functions out to z=1. More importantly, a joint
analysis can make dark energy constraints robust against systematic errors in
the shear-shear correlation and halo modeling.
