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arXiv · 2211.17181

Spin diffusion in perturbed isotropic Heisenberg spin chain

S. Nandy·Z. Lenarčič·E. Ilievski·M. Mierzejewski·J. Herbrych·P. Prelovšek
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Abstract

The isotropic Heisenberg chain represents a particular case of an integrable many-body system exhibiting superdiffusive spin transport at finite temperatures. Here, we show that this model has distinct properties also at finite magnetization $m\ne0$, even upon introducing the SU(2) invariant perturbations. Specifically, we observe nonmonotonic dependence of the diffusion constant ${\cal D}_0(\Delta)$ on the spin anisotropy $\Delta$, with a pronounced maximum at $\Delta =1$. The latter dependence remains true also in the zero magnetization sector, with superdiffusion at $\Delta=1$ that is remarkably stable against isotropic perturbation (at least in finite-size systems), consistent with recent experiments with cold atoms.

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S. Nandy, Z. Lenarčič, E. Ilievski, M. Mierzejewski, J. Herbrych, P. Prelovšek. 2022-11-30. Spin diffusion in perturbed isotropic Heisenberg spin chain. https://doi.org/10.1103/physrevb.108.l081115

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