{
  "annotation_id": "ac077530-db38-4c3b-bfb9-b425e85cdf34",
  "date_created": "2026-03-02T18:02:10.131000Z",
  "date_modified": "2026-03-02T18:02:10.131000Z",
  "file_hash": "7c60d4102740a4d403c000290fb40000ca3c4d42b5021e38b512dfdef59f6d33",
  "private": false,
  "record": {
    "abstract": "We study theoretically and experimentally the quantum properties of a type II\nfrequency degenerate optical parametric oscillator below threshold with a\nquarter-wave plate inserted inside the cavity which induces a linear coupling\nbetween the orthogonally polarized signal and idler fields. This original\ndevice provides a good insight into general properties of two-mode gaussian\nstates, illustrated in terms of covariance matrix. We report on the\nexperimental generation of two-mode squeezed vacuum on non-orthogonal\nquadratures depending on the plate angle. After a simple operation, the\nentanglement is maximized and put into standard form, \\textit{i.e.} quantum\ncorrelations and anti-correlations on orthogonal quadratures. A half-sum of\nsqueezed variances as low as $0.33 \\pm 0.02$, well below the unit limit for\ninseparability, is obtained and the entanglement measured by the entropy of\nformation.",
    "arxiv_id": "quant-ph/0410081",
    "authors": [
      "Julien Laurat",
      "Thomas Coudreau",
      "Gaelle Keller",
      "Nicolas Treps",
      "Claude Fabre"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.71.022313",
    "journal_ref": "Physical Review A 71 (2005) 022313",
    "title": "Experimental Generation of Large Quadrature EPR Entanglement with a   Self-Phase-Locked Type II OPO Below Threshold",
    "url": "https://arxiv.org/abs/quant-ph/0410081"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "e78d4d27-ff46-4394-8a86-788f15fe502b",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}