J. Phys. I France
Volume 1, Numéro 5, May 1991
Page(s) 647 - 657
DOI: 10.1051/jp1:1991109
J. Phys. I France 1 (1991) 647-657

Extended proof of long-range order in the two-dimensional quantum spin-1/2 XXZ-model at T=0

Hans-Aloys Wischmann and Erwin Müller-Hartmann

Institut für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77, D-W 5000 Köln 41, Germany

(Received 25 January 1991, accepted 1 February 1991)

We prove the existence of long-range order (LRO) in the ground state of the 2D quantum spin-1/2 XXZ-model for all anisotropies $0\leqslant\Delta\leqslant 0.22$ and $\Delta\geqslant 1.47$. We achieve this extension of previous proofs by developing an improved variant of the Dyson-Lieb-Simon proof of LRO in quantum spin systems and by deriving improved upper and lower bounds for the ground state energy of the XXZ-model.

© Les Editions de Physique 1991

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.