{
  "annotation_id": "5fea2a7e-5b2f-49c5-bfc5-9cc6f94f9a5e",
  "date_created": "2026-03-02T18:02:10.392000Z",
  "date_modified": "2026-03-02T18:02:10.392000Z",
  "file_hash": "16a02016c38aefea19b8c6ff351178c4561cec606a56996eeffe8a390993a783",
  "private": false,
  "record": {
    "abstract": "We present a method to construct entanglement measures for pure states of\nmultipartite qubit systems. The key element of our approach is an antilinear\noperator that we call {\\em comb} in reference to the {\\em hairy-ball theorem}.\nFor qubits (or spin 1/2) the combs are automatically invariant under\n$SL(2,\\CC)$. This implies that the {\\em filters} obtained from the combs are\nentanglement monotones by construction. We give alternative formulae for the\nconcurrence and the 3-tangle as expectation values of certain antilinear\noperators. As an application we discuss inequivalent types of genuine\nfour-qubit entanglement.",
    "arxiv_id": "quant-ph/0410102",
    "authors": [
      "Andreas Osterloh",
      "Jens Siewert"
    ],
    "categories": [
      "quant-ph",
      "math-ph",
      "math.MP"
    ],
    "doi": "10.1103/PhysRevA.72.012337",
    "journal_ref": "Phys. Rev. A 72, 012337 (2005)",
    "title": "Constructing N-qubit entanglement monotones from anti-linear operators",
    "url": "https://arxiv.org/abs/quant-ph/0410102"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "7d676d8e-20e3-4470-8c14-780a49222331",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}