{
  "annotation_id": "4104fab2-0bc3-4b5d-b7f8-50e2fc0b30ff",
  "date_created": "2026-03-02T18:01:59.920000Z",
  "date_modified": "2026-03-02T18:01:59.920000Z",
  "file_hash": "1326805afedd3c9fc9ec7bdfa21e166bda2dd5fc3684f651cb39c967a603c7ec",
  "private": false,
  "record": {
    "abstract": "We present a systematic study of the purity for Gaussian states of\nsingle-mode continuous variable systems. We prove the connection of purity to\nobservable quantities for these states, and show that the joint measurement of\ntwo conjugate quadratures is necessary and sufficient to determine the purity\nat any time. The statistical reliability and the range of applicability of the\nproposed measurement scheme is tested by means of Monte Carlo simulated\nexperiments. We then consider the dynamics of purity in noisy channels. We\nderive an evolution equation for the purity of general Gaussian states both in\nthermal and squeezed thermal baths. We show that purity is maximized at any\ngiven time for an initial coherent state evolving in a thermal bath, or for an\ninitial squeezed state evolving in a squeezed thermal bath whose asymptotic\nsqueezing is orthogonal to that of the input state.",
    "arxiv_id": "quant-ph/0304059",
    "authors": [
      "M. G. A. Paris",
      "F. Illuminati",
      "A. Serafini",
      "S. De Siena"
    ],
    "categories": [
      "quant-ph",
      "cond-mat"
    ],
    "doi": "10.1103/PhysRevA.68.012314",
    "journal_ref": "Phys. Rev. A 68, 012314 (2003)",
    "title": "Purity of Gaussian states: measurement schemes and time-evolution in   noisy channels",
    "url": "https://arxiv.org/abs/quant-ph/0304059"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "281509ae-b6e4-427c-9f93-247009440271",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}