Subdiffusive hydrodynamics of nearly integrable anisotropic spin chains.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35969776.
- Also identified by DOI 10.1073/pnas.2202823119 and PMC identifier 9407665.
- Licence recorded as CC BY-NC-ND.
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Abstract
We address spin transport in the easy-axis Heisenberg spin chain subject to different integrability-breaking perturbations. We find subdiffusive spin transport characterized by dynamical exponent <i>z</i> = 4 up to a timescale parametrically long in the anisotropy. In the limit of infinite anisotropy, transport is subdiffusive at all times; for finite anisotropy, one eventually recovers diffusion at late times but with a diffusion constant independent of the strength of the perturbation and solely fixed by the value of the anisotropy. We provide numerical evidence for these findings, and we show how they can be understood in terms of the dynamical screening of the relevant quasiparticle excitations and effective dynamical constraints. Our results show that the diffusion constant of near-integrable diffusive spin chains is generically not perturbative in the integrability-breaking strength.