{
  "id": "0905.3470",
  "version": "v4",
  "published": "2009-05-21T11:43:19.000Z",
  "updated": "2009-08-09T08:29:27.000Z",
  "title": "1/R Correction to Gravity in the Early Universe",
  "authors": [
    "Shi Pi",
    "Tower Wang"
  ],
  "comment": "27 pages, 7 figures, even more references added",
  "categories": [
    "astro-ph.CO",
    "gr-qc",
    "hep-th"
  ],
  "abstract": "To explain the accelerated expansion of late universe, the 1/R correction to Einstein gravity is usually considered, where R is the Ricci scalar. This correction term is generally believed to be negligible in the early universe. However, if the 1/R term is inflaton-dependent, it will dramatically change the story of inflation. The entropy perturbation will naturally appear and drive the evolution of curvature perturbation outside the Hubble horizon. In a large class of models, the entropy perturbation can be made nearly scale-invariant. In Einstein gravity the single-field inflation with a quartic potential has been ruled out by recent observations, but it revives when the 1/R term is turned on. The evolution of non-Gaussianities on large scale are also studied and applied to inflation with 1/R correction. In some specific models, a large non-Gaussianity can be naturally generated outside the horizon.",
  "revisions": [
    {
      "version": "v4",
      "updated": "2009-08-09T08:29:27.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "04.50.Kd",
      "98.80.Cq"
    ],
    "keywords": [
      "early universe",
      "einstein gravity",
      "entropy perturbation",
      "curvature perturbation outside",
      "quartic potential"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1103/PhysRevD.80.043503",
      "journal": "Physical Review D",
      "year": 2009,
      "month": "Aug",
      "volume": 80,
      "number": 4,
      "pages": "043503"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 27,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 821006,
      "adsabs": "2009PhRvD..80d3503P"
    }
  }
}