Density of states near the Mott-Hubbard transition in the limit of large dimensions

The zero temperature Mott-Hubbard transition as a function of the Coulomb repulsion U is investigated in the Limit of large dimensions. The behavior of the density of states near the transition at U = U-c is analyzed in all orders of the skeleton expansion. It is shown that only two transition scenarios are consistent with the skeleton expansion for U < U-c: (i) The Mott-Hubbard transition is "discontinuous" in the sense that in the density of states finite spectral weight is redistributed at U-c. (ii) The transition occurs via a point at U = U-c where the system is neither a Fermi liquid nor an insulator. [S0031-9007(98)07525-5].