{
  "id": "2205.15255",
  "version": "v1",
  "published": "2022-05-30T17:04:12.000Z",
  "updated": "2022-05-30T17:04:12.000Z",
  "title": "Superradiance and subradiance in a gas of two-level atoms",
  "authors": [
    "Hanzhen Ma",
    "Oriol Rubies-Bigorda",
    "Susanne F. Yelin"
  ],
  "comment": "30 pages, 11 figures",
  "categories": [
    "quant-ph"
  ],
  "abstract": "Cooperative effects describe atomic ensembles with exchange of photonic excitations, such as dipole-dipole interactions. As a particular example, superradiance arises from spontaneous emission when this exchange leads to constructive interference of the emitted photons. Here, we introduce an integrated method for studying cooperative radiation in many-body systems. This method, which allows to study extended systems with arbitrarily large number of particles can be formulated by an effective, nonlinear, two-atom master equation that describes the dynamics using a closed form which treats single- and many-body terms on an equal footing. We apply this method to a homogeneous gas of initially inverted two-level atoms, and demonstrate the appearance of both superradiance and subradiance, identifying a many-body coherence term as the source of these cooperative effects. We describe the many-body induced broadening - which is analytically found to scale with the optical depth of the system - and light shifts, and distinguish spontaneous effects from induced ones. In addition, we theoretically predict the time-dependence of subradiance, and the phase change of the radiated field during the cooperative decay.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-05-30T17:04:12.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "two-level atoms",
      "superradiance",
      "subradiance",
      "cooperative effects",
      "two-atom master equation"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 30,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}