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arXiv · 1608.05937

Spin correlation functions and quasiparticle decay

Igor Poboiko·Mikhail Feigel'man
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Abstract

We study one-dimensional anisotropic XXZ spin-$\frac12$ model with ferromagnetic sign of the coupling and $z-z$ exchange constant $J_z = \Delta J$, where $\Delta < 1$, and $J$ is the coupling within XY spin plane. We calculate damping of low-energy excitations with $\omega \ll T $ due to their scattering from thermal excitation bath with temperature $T \ll J$, taking into account nonzero curvature of the excitation spectrum, $\epsilon(q) = u q + \delta\epsilon(q)$. We calculate also longitudinal spin-spin correlation function $\langle S^z(x,t)S^z(0,0) \rangle$ at $x \approx ut$ and find the shape of the spreading "wave packet".

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Igor Poboiko, Mikhail Feigel'man. 2016-08-21. Spin correlation functions and quasiparticle decay. https://doi.org/10.1103/physrevb.94.195420

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