{
  "annotation_id": "00a07457-71e0-409b-8a4c-c566c7de9fd6",
  "date_created": "2026-03-02T18:02:43.873000Z",
  "date_modified": "2026-03-02T18:02:43.873000Z",
  "file_hash": "2075e61244e078c6272e9762bc28fcbacf73f09c22a9178642440feb07eb393e",
  "private": false,
  "record": {
    "abstract": "We present a generic way of thinking about time machines from the view of a\nfar away observer. In this model the universe consists of three (or more)\nregions: One containing the entrance of the time machine, another the exit and\nthe remaining one(s) the rest of the universe. In the latter we know ordinary\nquantum mechanics to be valid and thus are able to write down a Hamiltonian\ndescribing this generic time machine. We prove the time-evolution operator to\nbe non-symmetric. Various interpretations of this irreversibility are given.",
    "arxiv_id": "quant-ph/9805075",
    "authors": [
      "Frank Antonsen",
      "Karsten Bormann"
    ],
    "categories": [
      "quant-ph"
    ],
    "journal_ref": "Int.J.Theor.Phys. 37 (1998) 2383-2393",
    "title": "Time Machines and the Breakdown of Unitarity",
    "url": "https://arxiv.org/abs/quant-ph/9805075"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "570404ca-4796-42ec-b0cf-a99033e98e4e",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}