{
  "id": "1406.7139",
  "version": "v2",
  "published": "2014-06-27T10:15:07.000Z",
  "updated": "2014-10-16T20:13:39.000Z",
  "title": "Anisotropic stress as signature of non-standard propagation of gravitational waves",
  "authors": [
    "Ippocratis D. Saltas",
    "Ignacy Sawicki",
    "Luca Amendola",
    "Martin Kunz"
  ],
  "comment": "4 pages plus references. Version to appear in Physical Review Letters",
  "categories": [
    "astro-ph.CO",
    "gr-qc",
    "hep-th"
  ],
  "abstract": "We make precise the heretofore ambiguous statement that anisotropic stress is a sign of a modification of gravity. We show that in cosmological solutions of very general classes of models extending gravity --- all scalar-tensor theories (Horndeski), Einstein-Aether models and bimetric massive gravity --- a direct correspondence exists between perfect fluids apparently carrying anisotropic stress and a modification in the propagation of gravitational waves. Since the anisotropic stress can be measured in a model-independent manner, a comparison of the behavior of gravitational waves from cosmological sources with large-scale-structure formation could in principle lead to new constraints on the theory of gravity.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-06-27T10:15:07.000Z",
      "title": "Scalar anisotropic stress as signature of correction to gravitational waves",
      "abstract": "We make precise the heretofore ambiguous statement that anisotropic stress is a sign of a modification of gravity. We show that, in very general classes of models extending gravity -- all scalar-tensor theories (Horndeski), Einstein-Aether models and bimetric massive gravity -- a direct correspondence exists between the appearance of scalar anisotropic stress in cosmological solutions and a modification in the propagation of gravitational waves. If these phenomena are present, they are both active during the same cosmological time. The appearance of anisotropic stress is therefore an unambiguous signature of a modification of gravity. Since the anisotropic stress can be measured in a model-independent manner, a comparison of the behavior of gravitational waves from cosmological sources with large-scale-structure formation could in principle lead to new constraints on the theory of gravity.",
      "comment": "4 pages plus references",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-10-16T20:13:39.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "04.50.Kd",
      "98.80.-k",
      "04.30.-w"
    ],
    "keywords": [
      "scalar anisotropic stress",
      "gravitational waves",
      "correction",
      "modification",
      "heretofore ambiguous statement"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1103/PhysRevLett.113.191101",
      "journal": "Physical Review Letters",
      "year": 2014,
      "month": "Nov",
      "volume": 113,
      "number": 19,
      "pages": 191101
    },
    "note": {
      "typesetting": "TeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1303513,
      "adsabs": "2014PhRvL.113s1101S"
    }
  }
}