{
  "id": "1709.10096",
  "version": "v1",
  "published": "2017-09-28T17:59:04.000Z",
  "updated": "2017-09-28T17:59:04.000Z",
  "title": "Universal broadening of the light cone in low-temperature transport",
  "authors": [
    "Bruno Bertini",
    "Lorenzo Piroli",
    "Pasquale Calabrese"
  ],
  "comment": "6 pages, 3 figures",
  "categories": [
    "cond-mat.stat-mech",
    "cond-mat.quant-gas",
    "quant-ph"
  ],
  "abstract": "We consider the low-temperature transport properties of critical one-dimensional systems which can be described, at equilibrium, by a Luttinger liquid. We focus on the prototypical setting where two semi-infinite chains are prepared in two thermal states at small but different temperatures and suddenly joined together. At large distances $x$ and times $t$, conformal field theory predicts universal profiles of the energy density and current: a single light cone emerges, resulting in a three-step form of the profiles, with sharp transitions at the edges. Here we provide a generalization to arbitrary observables, which is obtainable by taking into account the generic nonlinearity of the spectrum. Using a universal nonlinear Luttinger liquid description, we show that generic observables still display a three-step form, but smooth peaks emerge at the edges of the light cone. These are described by a universal function of $\\zeta=x/t$ which we compute explicitly. In the case of interacting integrable models, we show that our predictions agree with the results of the generalized hydrodynamic approach.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-09-28T17:59:04.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "light cone",
      "low-temperature transport",
      "universal broadening",
      "universal nonlinear luttinger liquid description",
      "field theory predicts universal profiles"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}