{
  "id": "2411.02170",
  "version": "v2",
  "published": "2024-11-04T15:29:20.000Z",
  "updated": "2024-12-16T11:15:32.000Z",
  "title": "On (dis)agreement between different methods of calculation of the imaginary part of the effective action in expanding space-times",
  "authors": [
    "E. T. Akhmedov",
    "I. A. Belkovich",
    "D. V. Diakonov",
    "K. A. Kazarnovskii"
  ],
  "categories": [
    "hep-th"
  ],
  "abstract": "We consider two approaches to calculate imaginary parts of effective actions in expanding space-times. While the first approach uses Bogolyubov coefficients, the second one uses the functional integral or the Feynman propagator. In eternally expanding space-times these two approaches give different answers for the imaginary parts. The origin of the difference can be traced to the presence if the wave-functionals for the initial and final states in the functional integral. We show this explicitly on the example of the expanding Poincare patch of the de Sitter space-time.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2024-12-16T11:15:32.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "imaginary part",
      "expanding space-times",
      "effective action",
      "calculation",
      "functional integral"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}