{
  "annotation_id": "8cfa18a1-c254-48d9-b88d-3a16a2a4c5de",
  "date_created": "2026-03-02T18:02:20.750000Z",
  "date_modified": "2026-03-02T18:02:20.750000Z",
  "file_hash": "f14bef5b174db07a4e20528ea109f52ed443841246a6ca8bdf9b579c63f584a5",
  "private": false,
  "record": {
    "abstract": "We study a model of a two-level system (i.e. a qubit) in interaction with the\nelectromagnetic field. By means of homodyne detection, one field-quadrature is\nobserved continuously in time. Due to the interaction, information about the\ninitial state of the qubit is transferred into the field, thus influencing the\nhomodyne measurement results. We construct random variables (pointers) on the\nprobability space of homodyne measurement outcomes having distributions close\nto the initial distributions of sigma-x and sigma-z. Using variational\ncalculus, we find the pointers that are optimal. These optimal pointers are\nvery close to hitting the bound imposed by Heisenberg\u0027s uncertainty relation on\njoint measurement of two non-commuting observables. We close the paper by\ngiving the probability densities of the pointers.",
    "arxiv_id": "quant-ph/0510086",
    "authors": [
      "Bas Janssens",
      "Luc Bouten"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1088/0305-4470/39/11/013",
    "journal_ref": "J. Phys. A: Math. Gen. 39 (2006) 2773-2790",
    "title": "Optimal Pointers for Joint Measurement of sigma-x and sigma-z via   Homodyne Detection",
    "url": "https://arxiv.org/abs/quant-ph/0510086"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "3899ea34-2b7d-4dd1-a04b-314112566725",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}