Physical Review Letters
Correlated Lattice Fermions in d = ∞ Dimensions
Walter Metzner, D. Vollhardt
Abstract
We show that even in $d=\ensuremath{\infty}$ dimensions the Hubbard model, when scaled properly, describes nontrivial correlations among fermions. Diagrammatic treatments are found to be substantially simpler than in finite dimensions. The weak-coupling correlation energy is seen to be a good approximation for that in $d=3$. Recent approximations based on slave-boson techniques are recovered by the exact evaluation of explicit variational wave functions in $d=\ensuremath{\infty}$.