{
  "id": "cond-mat/0610341",
  "version": "v1",
  "published": "2006-10-12T14:37:19.000Z",
  "updated": "2006-10-12T14:37:19.000Z",
  "title": "Time-dependent density-functional theory beyond the adiabatic approximation: insights from a two-electron model system",
  "authors": [
    "C. A. Ullrich"
  ],
  "comment": "10 pages, 7 figures",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "Most applications of time-dependent density-functional theory (TDDFT) use the adiabatic local-density approximation (ALDA) for the dynamical exchange-correlation potential Vxc(r,t). An exact (i.e., nonadiabatic) extension of the ground-state LDA into the dynamical regime leads to a Vxc(r,t) with a memory, which causes the electron dynamics to become dissipative. To illustrate and explain this nonadiabatic behavior, this paper studies the dynamics of two interacting electrons on a two-dimensional quantum strip of finite size, comparing TDDFT within and beyond the ALDA with numerical solutions of the two-electron time-dependent Schroedinger equation. It is shown explicitly how dissipation arises through multiple particle-hole excitations, and how the nonadiabatic extension of the ALDA fails for finite systems, but becomes correct in the thermodynamic limit.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2006-10-12T14:37:19.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "time-dependent density-functional theory",
      "two-electron model system",
      "adiabatic approximation",
      "two-electron time-dependent schroedinger equation",
      "dynamical exchange-correlation potential vxc"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}