{
  "abstract": "We present a four-mode Fock-state photonics implementation of the variational quantum deflation (VQD) algorithm to calculate the ground-state and excited-state energies for the neutral helium atom in a CAS(2,2) Subspace. Its CAS(2,2) electronic Hilbert space is encoded into a bosonic Fock-space representation and subsequently optimized using a continuous-variable quantum circuit. The circuit architecture under study is constructed of single-mode phase shifts, beam splitters, and cross-Kerr interactions. The variational circuit is initialized in the Fock state $\\ket{1100}$ and its performance is benchmarked against exact diagonalization of the active-space configuration-interaction (CASCI) Hamiltonian. We also extend the method to optimize from the first to three excited states of the helium atom with the aid of the variational quantum deflation $(VQD)$ method in a CAS(2,2). We then investigate the performance of this circuit architecture as a basis for implementing the VQD method. In the ideal noiseless simulation setting, we see that the survival probability of the ground and the excited states within the target $CAS$ subspace is unity, because the total photon number and the photon number in the two spin sectors $α$ and $β$ are preserved. We demonstrate that the proposed approach enables the determination of the ground and excited-state energies within the CAS(2,2) electronic Hilbert space using a continuous-variable quantum circuit and the variational quantum deflation ($VQD$) algorithm, while satisfying the orthogonality conditions with negligible errors.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.06448",
  "author_total": 2,
  "authors": [
    {
      "name": "Forouzan Mirmasoudi"
    },
    {
      "name": "Badie Ghavami"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e4kh44232sh9w.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.06448",
  "fulltext_url": null,
  "id": "e4kh44232sh9w",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.06448",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "arxiv",
      "quant-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.06448",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/e4kh44232sh9w.ris",
  "sources": [
    {
      "first_seen": "2026-11-05T15:20:56Z",
      "native_id": "2611.06448",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.06448"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Helium States in a CAS(2,2) Subspace Inspired by Quantum Photonics",
  "title_text": "Helium States in a CAS(2,2) Subspace Inspired by Quantum Photonics",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:56Z",
  "url": "https://research.draconitic.com/paper/e4kh44232sh9w",
  "venue": "arXiv",
  "versions": []
}