{
  "annotation_id": "36f411eb-85f6-433a-99d6-7420b7451c95",
  "date_created": "2026-03-02T18:02:12.847000Z",
  "date_modified": "2026-03-02T18:02:12.847000Z",
  "file_hash": "3c1e09a951e3524a299d065eae5430524fe12ad5789d26ced345ce1282f174ab",
  "private": false,
  "record": {
    "abstract": "The connection between many-body theory (MBPT)--in perturbative and\nnon-perturbative form--and quantum-electrodynamics (QED) is reviewed for\nsystems of two fermions in an external field. The treatment is mainly based\nupon the recently developed covariant-evolution-operator method for QED\ncalculations [Lindgren et al. Phys. Rep. 389, 161 (2004)], which has a\nstructure quite akin to that of many-body perturbation theory. At the same time\nthis procedure is closely connected to the S-matrix and the Green\u0027s-function\nformalisms and can therefore serve as a bridge between various approaches. It\nis demonstrated that the MBPT-QED scheme, when carried to all orders, leads to\na Schroedinger-like equation, equivalent to the Bethe-Salpeter (BS) equation. A\nBloch equation in commutator form that can be used for an \"extended\" or\nquasi-degenerate model space is derived. It has the same relation to the BS\nequation as has the standard Bloch equation to the ordinary Schroedinger\nequation and can be used to generate a perturbation expansion compatible with\nthe BS equation also for a quasi-degenerate model space.",
    "arxiv_id": "quant-ph/0502141",
    "authors": [
      "Ingvar Lindgren"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1139/p05-027",
    "title": "Many-body-QED perturbation theory: Connection to the Bethe-Salpeter   equation",
    "url": "https://arxiv.org/abs/quant-ph/0502141"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "dc65e1e0-062c-4184-b15f-b3a89c8aae68",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}