{
  "annotation_id": "abc23f87-7f31-4d8a-960f-361d7abb4b46",
  "date_created": "2026-03-02T18:02:27.708000Z",
  "date_modified": "2026-03-02T18:02:27.708000Z",
  "file_hash": "044e2b4078d92b11ce56c2509b511eaff60aef7a5263f07195e2a9b526375c0f",
  "private": false,
  "record": {
    "abstract": "A simplified Heisenberg spin model is studied in order to examine the idea of\ndecoherence in closed quantum systems. For this purpose, we present a\nquantifiable definition to quantum coherence $\\Xi$, and discuss in some detail\na general coherence theory and its elementary results. As expected, decoherence\nis understood as a statistical process that is caused by the dynamics of the\nsystem, similar to the growth of entropy. It appears that coherence is an\nimportant measure that helps to understand quantum properties of a system,\ne.g., the decoherence time can be derived from the coherence function $\\Xi(t)$,\nbut not from the entropy dynamics. Moreover, the concept of decoherence time is\napplicable in closed and finite systems. However, in most cases, the decay of\noff-diagonal elements differs from the usual $\\exp(-t/\\tau_{\\rm d})$ behaviour.\nFor concreteness, we report the form of decoherence time $\\tau_{\\rm d}$ in a\nfinite Heisenberg model with respect to the number of particles $N$, density\n$n_{\\rho}$, spatial dimension $D$ and $\\epsilon$ in a $\\eta/r^{\\epsilon}$-type\nof potential.",
    "arxiv_id": "quant-ph/0605167",
    "authors": [
      "Olavi Dannenberg"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1002/andp.200710300",
    "journal_ref": "Ann. Phys. (Berlin) 17, No. 6, 355-373 (2008)",
    "title": "Coherence theory and coherence phenomena in a closed spin-1/2 system",
    "url": "https://arxiv.org/abs/quant-ph/0605167"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "fd9f5fc5-3c85-4c47-ab74-905985d6e1f4",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}