Density-matrix renormalization group for fermions: Convergence to the infinite-size limit

The density-matrix real-space renormalization-group approach is applied to the one-dimensional Hubbard model, to investigate the properties of convergence of the algorithm to a fixed orbit as the infinite-size (thermodynamic) limit is approached. We find that this convergence, which depends on the physical parameters of the model, is generally good. The interplay between the truncation of the Hilbert space and the thermodynamic limit, as well as the reasons and consequences of the existence of a fixed orbit are discussed. (C) 1997 Elsevier Science B.V.