Spin correlation functions and quasiparticle decay

Abstract

We study one-dimensional anisotropic XXZ spin-$\frac{1}{2}$ 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, $\epsilon (q)=uq+\delta \epsilon (q)$. We calculate also longitudinal spin-spin correlation function $⟨S^z(x,t)S^z(0,0)⟩$ at $x\approx ut$ and find the shape of the spreading "wave packet".

12 pages, 4 figures

References in corpus (4)

• Many body localization and thermalization in quantum statistical mechanics
• Absence of diffusion in an interacting system of spinless fermions on a one-dimensional disordered lattice
• Conservation laws, integrability and transport in one-dimensional quantum systems
• Equilibration in a chiral Luttinger liquid