Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 65: Low-Dimensional Systems: 1D – Theory

TT 65.7: Talk

Wednesday, March 18, 2015, 16:45–17:00, H 0104

Form Factor Expansions for the XXZ Chain in the Massive Regime — •Maxime Dugave and Frank Göhmann — Bergische Universität Wuppertal

We discuss the form factor approach to correlation functions of the integrable anisotropic spin-1/2 Heisenberg chain in the massive regime at zero temperature.

Using the transfer-matrix technique and Bethe ansatz, we characterize the spectrum of the Hamiltonian in the thermodynamic limit. By analyzing the non-linear integral equations which describe excited states, we rederive the classification of excitations found by Babelon, De Vega and Viallet (1983) and correct an error in the higher-level Bethe equations obtained in this classical work.

This lays the basis for the calculation of exact expressions for matrix elements of local operators in the thermodynamic limit. In the 2-particle case, we find agreement with results from the vertex operator approach (Jimbo and Miwa (1995), Lashkevich (2002)). We eventually obtain the leading large-distance asymptotics of the longitudinal correlation functions by a saddle-point integration.