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TT: Tiefe Temperaturen

TT 14: Postersitzung II: Korrelierte Systeme(1-40), Theorie der Supraleitung(41-50), Metall-Isolator-Übergang, Lokalisierung(51-66), Niederdimensionale Systeme, Quantenhalleffekt(67-80), Pinning, kritische Ströme und Vortexdynamik(81-93), HTSL-Drähte und -Bänder(94-98), Massive HTSL(99-104), supraleitende Borkarbide(105-109)

TT 14.10: Poster

Mittwoch, 19. März 1997, 15:00–18:30, Z1

Two−spinon dynamic structure factor of the one−dimensional s=1/2 Heisenberg−Ising antiferromagnet — •M. Karbach^1,2, G. M"uller², and A.H. Bougourzi³ — ¹BUGH Wuppertal, D-42097 Wuppertal — ²University of Rhode Island, Department of Physics, Kingston, RI 02881, USA — ³Institute of Theoretical Physics, SUNY at Stony Brook, NY 11794 USA

The exact 2-spinon part of the dynamic spin structure factor S_xx(Q,ω) for the one-dimensional s=1/2 XXZ model at T=0 in the antiferromagnetically ordered phase is calculated on the basis of recent advances by Jimbo and Miwa in the algebraic analysis of this model and the related vertex models. The dominant nature of the 2-spinon spectral weight in S_xx(Q,ω) is established via sum rules. The limiting cases of the new exact results for zero anisotropy and infinite anisotropy are discussed to establish links with a previous exact result for the Heisenberg model and with results of perturbation calculations near the Ising limit, respectively.