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arXiv · 0902.2402

Finite Temperature Dynamical Structure Factor of the Heisenberg-Ising Chain

A. J. A. James·W. D. Goetze·F. H. L. Essler
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Abstract

We consider the spin-1/2 Heisenberg XXZ chain in the regime of large Ising-like anisotropy $Δ$. By a combination of duality and Jordan-Wigner transformations we derive a mapping to weakly interacting spinless fermions, which represent domain walls between the two degenerate ground states. We develop a perturbative expansion in $1Δ$ for the transverse dynamical spin structure factor at finite temperatures and in an applied transverse magnetic field. We present a unified description for both the low-energy temperature-activated response and the temperature evolution of the T=0 two-spinon continuum. We find that the two-spinon continuum narrows in energy with increasing temperature. At the same time spectral weight is transferred from the two-spinon continuum to the low energy intraband scattering continuum, which is strongly peaked around the position of the (single) spinon dispersion (`Villain mode').

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A. J. A. James, W. D. Goetze, F. H. L. Essler. 2009-02-21. Finite Temperature Dynamical Structure Factor of the Heisenberg-Ising Chain. https://doi.org/10.1103/physrevb.79.214408

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