Abstract
A simple coupled-cluster-type approximation is introduced, which generalizes in momentum (k) space a method recently presented in the literature for real space, and tested on the exactly solvable XXZ anisotropic quantum antiferromagnetic spin-1/2 chain. We implement our approximation in k space on the fermionized version of this model, and obtain improved results, with remarkable quantitative and qualitative features.
- Received 23 November 1993
DOI:https://doi.org/10.1103/PhysRevB.49.9548
©1994 American Physical Society