Dynamical mean-field theory calculation with the dynamical density-matrix renormalization group

We study the Hubbard model at half band-filling on a Bethe lattice with infinite coordination number at zero temperature. We use the dynamical mean-field theory (DMFT) mapping to a single-impurity Anderson model with a bath whose properties have to be determined self-consistently. For a controlled and systematic implementation of the self-consistency scheme we use the fixed-energy approach to the DMFT. Using the dynamical density matrix renormalization group method (DDMRG) we calculate the density of states (DOS) with a resolution ranging from 3% of the bare bandwidth W = 4t at high energies to 0.01 % for the quasi-particle peak. The DDMRG resolution and accuracy for the DOS is superior to those obtained with other numerical methods in previous DMFT investigations. We find that the critical couplings are Uc,1/t = 4.45 +/- 0.05 and Uc,2/t = 6.1 +/- 0. 1. Our calculation indicate the existence of two metallic solutions below U = Uc,1. (c) 2006 Elsevier B.V. All rights reserved.