Wolf, Dietrich; Zittartz, Johannes:
On the one-dimensional spin-1/2-Chain and its related fermion model
1981
In: Zeitschrift für Physik. B Condensed Matter, Jg. 43 (1981), Heft 2, S. 173 - 183
Artikel/Aufsatz in Zeitschrift / Fach: Physik
Titel:
On the one-dimensional spin-1/2-Chain and its related fermion model
Autor(in):
Wolf, Dietrich im Online-Personal- und -Vorlesungsverzeichnis LSF anzeigen; Zittartz, Johannes
Erscheinungsjahr:
1981
Erschienen in:
Zeitschrift für Physik. B Condensed Matter, Jg. 43 (1981), Heft 2, S. 173 - 183
ISSN:
DOI:
Signatur der UB:

Abstract:

We study the linear anisotropic spin-1/2-Heisenberg model with periodic as well as antiperiodic boundary conditions. Using two assumptions about the eigenvalues of the related fermion models it is shown, how the exactly known energy spectrum of the periodic Heisenberg model is altered in the antiperiodic case. This investigation provides the basis for a subsequent test of a Hartree-Fock approximation. It gives fairly good results for the groundstate energy and the energy dispersion of low-lying excitations. Hartree-Fock solutions with gapless excitations yield a qualitatively correct picture of the phase diagram of the Heisenberg model.