Density matrix renormalization group calculation of correlation functions in one dimensional Hubbard model

摘要

We have studied correlation functions of the one dimensional Hubbard model using the density-matrix numerical renormalization group approach. The singularity exponents of the momentum distribution at k = k(sub F) and k = 3k(sub F), as well as the power-law singularity of the spin correlation function are computed for large U (U/t = 10(sup 3)). The momentum distribution exponent at k = k(sub F) and the spin correlation exponent are in agreement with the analytic results, while the calculated exponent for momentum distribution at k = 3k(sub F) is about 3/4 which disagrees with the analytical predicted value 9/8. We also discuss several new techniques for an accurate calculation of the correlation functions. (author). 16 refs, 5 figs, 1 tab. (Atomindex citation 26:070810)