{
  "id": "1904.01039",
  "version": "v1",
  "published": "2019-04-01T18:05:23.000Z",
  "updated": "2019-04-01T18:05:23.000Z",
  "title": "Anomalous relaxation and the high-temperature structure factor of XXZ spin chains",
  "authors": [
    "Sarang Gopalakrishnan",
    "Romain Vasseur",
    "Brayden Ware"
  ],
  "comment": "7pp, 2 figures, plus 4pp. supplemental material",
  "categories": [
    "cond-mat.stat-mech",
    "cond-mat.quant-gas",
    "cond-mat.str-el",
    "quant-ph"
  ],
  "abstract": "We compute the spin structure factor of XXZ spin chains in the Heisenberg and gapped (Ising) regimes in the high-temperature limit for nonzero magnetization, within the framework of generalized hydrodynamics including diffusive corrections. The structure factor shows a hierarchy of timescales in the gapped phase, owing to $s$-spin magnon bound states (`strings') of various sizes. Although short strings move ballistically, long strings move primarily diffusively as a result of their collisions with short strings. The interplay between these effects gives rise to anomalous power-law decay of the spin structure factor, with continuously varying exponents, at any fixed separation in the late-time limit. We elucidate the crossover to diffusion (in the gapped phase) and to superdiffusion (at the isotropic point) in the half-filling limit. We verify our results via extensive matrix product operator calculations.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-04-01T18:05:23.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "xxz spin chains",
      "high-temperature structure factor",
      "anomalous relaxation",
      "spin structure factor",
      "spin magnon bound states"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}