  We use Brueckner-Goldstone perturbation theory to calculate the ground-state
energy of the half-filled Hubbard model in infinite dimensions up to fourth
order in the Hubbard interaction. We obtain the momentum distribution as a
functional derivative of the ground-state energy with respect to the bare
dispersion relation. The resulting expressions agree with those from
Rayleigh-Schroedinger perturbation theory. Our results for the momentum
distribution and the quasi-particle weight agree very well with those obtained
earlier from Feynman-Dyson perturbation theory for the single-particle
self-energy. We give the correct fourth-order coefficient in the ground-state
energy which was not calculated accurately enough from Feynman-Dyson theory due
to the insufficient accuracy of the data for the self-energy, and find a good
agreement with recent estimates from Quantum Monte-Carlo calculations.
