The truncated Lanczos method using a variational scheme based on Hilbert space reduction as well as a local basis change [Dagotto et al., Phys. Rev. B 58, 12 063 (1998)] is reexamined. The energy is extrapolated as a power-law function of the Hamiltonian variance. This systematic extrapolation procedure is tested quantitatively on the two-leg t-J ladder doped with two holes. For this purpose, we have carried out calculations of the spin gap and of the pair dispersion up to size 2×15.
Physical Review B
- Pub Date:
- March 2001
- Strongly correlated electron systems;
- heavy fermions;
- Condensed Matter - Strongly Correlated Electrons
- 5 pages, 4 included eps figures, submitted to Phys. Rev. B