{
  "annotation_id": "c5ff14e6-6e7a-4a58-939d-f9c904004cef",
  "date_created": "2026-03-02T18:02:38.069000Z",
  "date_modified": "2026-03-02T18:02:38.069000Z",
  "file_hash": "78abf5688fed99e7d90ef1458a9a8f778041caa3dd8026fe6bd62edbeb857706",
  "private": false,
  "record": {
    "abstract": "In standard quantum theory, the ideas of information-entropy and of pure\nstates are closely linked. States are represented by density matrices $\\rho$ on\na Hilbert space and the information-entropy $-tr(\\rho\\log\\rho)$ is minimised on\npure states (pure states are the vertices of the boundary of the convex set of\nstates). The space of decoherence functions in the consistent histories\napproach to generalised quantum theory is also a convex set. However, by\nshowing that every decoherence function can be written as a convex combination\nof two other decoherence functions we demonstrate that there are no `pure\u0027\ndecoherence functions.\n  The main content of the paper is a new notion of information-entropy in\ngeneralised quantum mechanics which is applicable in contexts in which there is\nno a priori notion of time. Information-entropy is defined first on consistent\nsets and then we show that it decreases upon refinement of the consistent set.\nThis information-entropy suggests an intrinsic way of giving a consistent set\nselection criterion.",
    "arxiv_id": "quant-ph/9612035",
    "authors": [
      "C. J. Isham",
      "N. Linden"
    ],
    "categories": [
      "quant-ph"
    ],
    "title": "Information-entropy and the space of decoherence functions in   generalised quantum theory",
    "url": "https://arxiv.org/abs/quant-ph/9612035"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "45391943-60dc-41b9-9147-0adbe866e8e7",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}