{
  "annotation_id": "cff20946-928a-4392-8e31-1a05c434e56d",
  "date_created": "2026-03-02T18:02:41.359000Z",
  "date_modified": "2026-03-02T18:02:41.359000Z",
  "file_hash": "a0db45ffe135a4bfedabd40d2655a4c3375d7a802dc09ff5d342f5ae39e26516",
  "private": false,
  "record": {
    "abstract": "The present paper deals with the quantum coordinates of an event in\nspace-time, individuated by a quantum object. It is known that these\nobservables cannot be described by self-adjoint operators or by the\ncorresponding spectral projection-valued measure. We describe them by means of\na positive-operator-valued (POV) measure in the Minkowski space-time,\nsatisfying a suitable covariance condition with respect to the Poincare\u0027 group.\nThis POV measure determines the probability that a measurement of the\ncoordinates of the event gives results belonging to a given set in space-time.\nWe show that this measure must vanish on the vacuum and the one-particle\nstates, which cannot define any event. We give a general expression for the\nPoincare\u0027 covariant POV measures. We define the baricentric events, which lie\non the world-line of the centre-of-mass, and we find a simple expression for\nthe average values of their coordinates. Finally, we discuss the conditions\nwhich permit the determination of the coordinates with an arbitrary accuracy.",
    "arxiv_id": "quant-ph/9805030",
    "authors": [
      "Marco Toller"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.59.960",
    "journal_ref": "Phys.Rev.A59:960,1999",
    "title": "Localization of Events in Space-Time",
    "url": "https://arxiv.org/abs/quant-ph/9805030"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "0f8ac857-93b0-4ea1-acac-a99a9d67761d",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}