{
  "id": "cond-mat/0502045",
  "version": "v1",
  "published": "2005-02-02T10:03:54.000Z",
  "updated": "2005-02-02T10:03:54.000Z",
  "title": "On Which Length Scales Can Temperature Exist in Quantum Systems?",
  "authors": [
    "Michael Hartmann",
    "Guenter Mahler",
    "Ortwin Hess"
  ],
  "comment": "To appear in: Proceedings of the SPQS conference, J. Phys. Soc. Jpn. 74 (2005) Suppl",
  "journal": "J. Phys. Soc. Jpn. 74 (Suppl.), p. 26-29 (2005)",
  "categories": [
    "cond-mat.stat-mech",
    "cond-mat.str-el",
    "quant-ph"
  ],
  "abstract": "We consider a regular chain of elementary quantum systems with nearest neighbor interactions and assume that the total system is in a canonical state with temperature $T$. We analyze under what condition the state factors into a product of canonical density matrices with respect to groups of $n$ subsystems each, and when these groups have the same temperature $T$. While in classical mechanics the validity of this procedure only depends on the size of the groups $n$, in quantum mechanics the minimum group size $n_{\\text{min}}$ also depends on the temperature $T $! As examples, we apply our analysis to different types of Heisenberg spin chains.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2005-02-02T10:03:54.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "length scales",
      "temperature",
      "nearest neighbor interactions",
      "elementary quantum systems",
      "heisenberg spin chains"
    ],
    "tags": [
      "conference paper",
      "journal article"
    ],
    "publication": {
      "doi": "10.1143/JPSJS.74S.26",
      "journal": "Journal of the Physical Society of Japan",
      "year": 2005,
      "month": "Jan",
      "volume": 74,
      "pages": 26
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2005JPSJ...74S..26H"
    }
  }
}