{
  "id": "0704.0793",
  "version": "v2",
  "published": "2007-04-06T16:17:14.000Z",
  "updated": "2007-11-14T17:19:05.000Z",
  "title": "Friedmann Equations and Thermodynamics of Apparent Horizons",
  "authors": [
    "Yungui Gong",
    "Anzhong Wang"
  ],
  "comment": "no figures, V2: re-organized and re-writtend, main results and conclusion unchanged, Phys. Rev. Lett. in press",
  "journal": "Phys.Rev.Lett.99:211301,2007",
  "doi": "10.1103/PhysRevLett.99.211301",
  "categories": [
    "hep-th",
    "astro-ph",
    "gr-qc"
  ],
  "abstract": "With the help of a masslike function which has dimension of energy and equals to the Misner-Sharp mass at the apparent horizon, we show that the first law of thermodynamics of the apparent horizon $dE=T_AdS_A$ can be derived from the Friedmann equation in various theories of gravity, including the Einstein, Lovelock, nonlinear, and scalar-tensor theories. This result strongly suggests that the relationship between the first law of thermodynamics of the apparent horizon and the Friedmann equation is not just a simple coincidence, but rather a more profound physical connection.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2007-11-14T17:19:05.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "04.70.Dy",
      "98.80.-k",
      "04.20.Cv"
    ],
    "keywords": [
      "apparent horizon",
      "friedmann equation",
      "thermodynamics",
      "first law",
      "misner-sharp mass"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review Letters",
      "year": 2007,
      "month": "Nov",
      "volume": 99,
      "number": 21,
      "pages": 211301
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 748131,
      "adsabs": "2007PhRvL..99u1301G"
    }
  }
}