{
  "annotation_id": "027756ab-cf56-4f9c-ba41-78430b67e79a",
  "date_created": "2026-03-02T18:02:03.629000Z",
  "date_modified": "2026-03-02T18:02:03.629000Z",
  "file_hash": "05726c69067c0468f31c413d6d41c7b20840692f9489868d90c4636e2fe40303",
  "private": false,
  "record": {
    "abstract": "The reduced dynamics of a central spin coupled to a bath of N spin-1/2\nparticles arranged in a spin star configuration is investigated. The exact time\nevolution of the reduced density operator is derived, and an analytical\nsolution is obtained in the limit of an infinite number of bath spins, where\nthe model shows complete relaxation and partial decoherence. It is demonstrated\nthat the dynamics of the central spin cannot be treated within the Born-Markov\napproximation. The Nakajima-Zwanzig and the time-convolutionless projection\noperator technique are applied to the spin star system. The performance of the\ncorresponding perturbation expansions of the non-Markovian equations of motion\nis examined through a comparison with the exact solution.",
    "arxiv_id": "quant-ph/0401051",
    "authors": [
      "Heinz-Peter Breuer",
      "Daniel Burgarth",
      "Francesco Petruccione"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevB.70.045323",
    "journal_ref": "Physical Review B 70, 045323 (2004)",
    "title": "Non-Markovian dynamics in a spin star system: Exact solution and   approximation techniques",
    "url": "https://arxiv.org/abs/quant-ph/0401051"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "3dd53282-b920-43a4-81a8-0e03f78c802a",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}