{
  "annotation_id": "f9e295a2-5331-40b0-8c7e-291815d062ff",
  "date_created": "2026-03-02T18:02:00.212000Z",
  "date_modified": "2026-03-02T18:02:00.212000Z",
  "file_hash": "3fbf8381a98eb38650bde7834eb94721a61294e031581115904e86e96df0f75a",
  "private": false,
  "record": {
    "abstract": "The concept of off-diagonal geometric phases for mixed quantal states in\nunitary evolution is developed. We show that these phases arise from three\nbasic ideas: (1) fulfillment of quantum parallel transport of a complete basis,\n(2) a concept of mixed state orthogonality adapted to unitary evolution, and\n(3) a normalization condition. We provide a method for computing the\noff-diagonal mixed state phases to any order for unitarities that divide the\nparallel transported basis of Hilbert space into two parts: one part where each\nbasis vector undergoes cyclic evolution and one part where all basis vectors\nare permuted among each other. We also demonstrate a purification based\nexperimental procedure for the two lowest order mixed state phases and consider\na physical scenario for a full characterization of the qubit mixed state\ngeometric phases in terms of polarization-entangled photon pairs. An\nalternative second order off-diagonal mixed state geometric phase, which can be\ntested in single-particle experiments, is proposed.",
    "arxiv_id": "quant-ph/0307012",
    "authors": [
      "Stefan Filipp",
      "Erik Sj\u00f6qvist"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.68.042112",
    "journal_ref": "Phys. Rev. A 68, 042112 (2003)",
    "title": "Off-diagonal generalization of the mixed state geometric phase",
    "url": "https://arxiv.org/abs/quant-ph/0307012"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "a5f9ae9d-dbd3-4daa-9f6b-f6b0f19dbe45",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}