{
  "annotation_id": "3724f88a-3675-4c88-8516-1abd961eaeda",
  "date_created": "2026-03-02T18:01:49.071000Z",
  "date_modified": "2026-03-02T18:01:49.071000Z",
  "file_hash": "9acae11209ece19657392fe05f1f3a7ee26584ce036c6f3b17821d5af2bffcc2",
  "private": false,
  "record": {
    "abstract": "We investigate the evolution of a single qubit subject to a continuous\nunitary dynamics and an additional interrupting influence which occurs\nperiodically. One may imagine a dynamically evolving closed quantum system\nwhich becomes open at certain times. The interrupting influence is represented\nby an operation, which is assumed to equivalently describe a non-selective\nunsharp measurement. It may be decomposed into a positive operator, which in\ncase of a measurement represents the pure measurement part, followed by an\nunitary back-action operator. Equations of motion for the state evolution are\nderived in the form of difference equations. It is shown that the \u0027free\u0027\nHamiltonian is completed by an averaged Hamiltonian, which goes back to the\nback-action. The positive operator specifies a decoherence rate and results in\na decoherence term. The continuum limit to a master equation is performed. The\nselective evolution is discussed and correcting higher order terms are worked\nout in an Appendix.",
    "arxiv_id": "quant-ph/0201078",
    "authors": [
      "Juergen Audretsch",
      "Lajos Diosi",
      "Thomas Konrad"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.66.022310",
    "title": "Evolution of a qubit under the influence of a succession of unsharp   measurements",
    "url": "https://arxiv.org/abs/quant-ph/0201078"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "ef0589c0-9b46-452a-8fcf-928849fb123e",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}