  We present a novel scheme for nuclear structure calculations based on
realistic nucleon-nucleon potentials. The essential ingredient is the explicit
treatment of the dominant interaction-induced correlations by means of the
Unitary Correlation Operator Method (UCOM). Short-range central and tensor
correlations are imprinted into simple, uncorrelated many-body states through a
state-independent unitary transformation. Applying the unitary transformation
to the realistic Hamiltonian leads to a correlated, low-momentum interaction,
well suited for all kinds of many-body models, e.g., Hartree-Fock or
shell-model. We employ the correlated interaction, supplemented by a
phenomenological correction to account for genuine three-body forces, in the
framework of variational calculations with antisymmetrised Gaussian trial
states (Fermionic Molecular Dynamics). Ground state properties of nuclei up to
mass numbers A<~60 are discussed. Binding energies, charge radii, and charge
distributions are in good agreement with experimental data. We perform angular
momentum projections of the intrinsically deformed variational states to
extract rotational spectra.
