{
  "id": "2012.08650",
  "version": "v1",
  "published": "2020-12-15T22:18:25.000Z",
  "updated": "2020-12-15T22:18:25.000Z",
  "title": "Rigidity and Superfast Signal Propagation in Fluids and Solids in Non-Equilibrium Steady States",
  "authors": [
    "T. R. Kirkpatrick",
    "D. Belitz",
    "J. R. Dorfman"
  ],
  "comment": "9pp, 2 figs",
  "categories": [
    "cond-mat.stat-mech",
    "cond-mat.soft"
  ],
  "abstract": "In the 1980s it was theoretically predicted that correlations of various observables in a fluid in a non-equilibrium steady state (NESS) are extraordinarily long-ranged, extending, in a well-defined sense, over the size of the system. This is to be contrasted with correlations in an equilibrium fluid, whose range is typically just a few particle diameters. These NESS correlations were later confirmed by numerous experimental studies. Unlike long-ranged correlations at critical points, these correlations are generic in the sense that they exist for any temperature as long as the system is in a NESS. In equilibrium systems, generic long-ranged correlations are caused by spontaneously broken continuous symmetries and are associated with a generalized rigidity, which in turn leads to a new propagating excitation or mode. For example, in a solid, spatial rigidity leads to transverse sound waves, while in a superfluid, phase rigidity leads to temperature waves known as second sound at finite temperatures, and phonons at zero temperature. More generally, long-ranged spatial correlations imply rigidity irrespective of their physical origin. This implies that a fluid in a NESS should also display a type of rigidity and related anomalous transport behavior. Here we show that this is indeed the case. For the particular case of a simple fluid in a constant temperature gradient, the anomalous transport behavior takes the form of a super-diffusive spread of a constant-pressure temperature perturbation. We also discuss the case of an elastic solid, where we predict a spread that is faster than ballistic.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-12-15T22:18:25.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "non-equilibrium steady state",
      "superfast signal propagation",
      "spatial correlations imply rigidity",
      "temperature",
      "correlations imply rigidity irrespective"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}