{
  "annotation_id": "63345ea3-b25c-4b99-836d-d347c8d94751",
  "date_created": "2026-03-02T18:02:33.777000Z",
  "date_modified": "2026-03-02T18:02:33.777000Z",
  "file_hash": "ae7e7858265b210fd60e6700fb7faf74c0ffc9c980b4aabb4d9cdb3889908c50",
  "private": false,
  "record": {
    "abstract": "We address binary and quaternary communication channels based on correlated\nmultiphoton two-mode states of radiation in the presence of losses. The\nprotocol are based on photon number correlations and realized upon choosing a\nshared set of thresholds to convert the outcome of a joint photon number\nmeasurement into a symbol from a discrete alphabet. In particular, we focus on\nchannels build using feasible photon-number entangled states (PNES) as two-mode\ncoherently-correlated (TMC) or twin-beam (TWB) states and compare their\nperformances with that of channels built using feasible classically correlated\n(separable) states. We found that PNES provide larger channel capacity in the\npresence of loss, and that TWB-based channels may transmit a larger amount of\ninformation than TMC-based ones at fixed energy and overall loss. Optimized bit\ndiscrimination thresholds, as well as the corresponding maximized mutual\ninformation, are explicitly evaluated as a function of the beam intensity and\nthe loss parameter. The propagation of TMC and TWB in lossy channels is\nanalyzed and the joint photon number distribution is evaluated, showing that\nthe beam statistics, either sub-Poissonian for TMC or super-Poissonian for TWB,\nis not altered by losses. Although entanglement is not strictly needed to\nestablish the channels, which are based on photon-number correlations owned\nalso by separable mixed states, purity of the support state is relevant to\nincrease security. The joint requirement of correlation and purity individuates\nPNES as a suitable choice to build effective channels. The effects of losses on\nchannel security are briefly discussed.",
    "arxiv_id": "quant-ph/0612028",
    "authors": [
      "Vladyslav C. Usenko",
      "Matteo G. A. Paris"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.75.043812",
    "journal_ref": "Phys. Rev. A 75, 043812 (2007)",
    "title": "Multiphoton communication in lossy channels with photon-number entangled   states",
    "url": "https://arxiv.org/abs/quant-ph/0612028"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "f49b79d6-c79e-4e93-b3dd-b413e74de24d",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}