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arXiv · 1412.8217

On form-factor expansions for the XXZ chain in the massive regime

M. Dugave·F. Göhmann·K. K. Kozlowski·J. Suzuki
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Abstract

We study the large-volume-$L$ limit of form factors of the longitudinal spin operators for the XXZ spin-$1/2$ chain in the massive regime. We find that the individual form factors decay as $L^{-n}$, $n$ being an even integer counting the number of physical excitations -- the holes -- that constitute the excited state. Our expression allows us to derive the form-factor expansion of two-point spin-spin correlation functions in the thermodynamic limit $L\rightarrow +\infty$. The staggered magnetisation appears naturally as the first term in this expansion. We show that all other contributions to the two-point correlation function are exponentially small in the large-distance regime.

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M. Dugave, F. Göhmann, K. K. Kozlowski, J. Suzuki. 2014-12-28. On form-factor expansions for the XXZ chain in the massive regime. https://doi.org/10.1088/1742-5468/2015/05/p05037

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