{
  "abstract": "We characterize the exact trade-off between internal and external entanglement in asymmetric two-mode Gaussian states at fixed local symplectic eigenvalues. Internal entanglement is quantified by the negativity $\\mathcal{N}_{A:B}$ between the two modes, while external entanglement is quantified by the negativity $\\mathcal{N}_{AB:CD}$ across a Gaussian purification. Numerical sampling suggests the boundary structure of the attainable region in the $(\\mathcal{N}_{AB:CD},\\mathcal{N}_{A:B})$ plane, which we then determine analytically. Parametrizing the global symplectic spectrum yields a closed admissible interval for the remaining spectral parameter at fixed $\\mathcal{N}_{AB:CD}$. We prove constructively that every point in this interval corresponds to a physical covariance matrix, implying that all intermediate values of $\\mathcal{N}_{A:B}$ between the resulting sharp bounds are achievable. The upper bound is attained for opposite-sign correlations of equal magnitude, while the positive branch of the lower bound occurs when one global symplectic eigenvalue equals unity. We also identify two external-entanglement thresholds, derive a saturated monogamy-type inequality, and recover the symmetric-state limit.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.35183",
  "author_total": 1,
  "authors": [
    {
      "name": "Yasusada Nambu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dq5049f0q0wga.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.35183",
  "fulltext_url": null,
  "id": "dq5049f0q0wga",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.35183",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "1702|Quantum Information and Cryptography"
    ]
  ],
  "openalex": "W7223799914",
  "pdf_url": "https://arxiv.org/pdf/2610.35183",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dq5049f0q0wga.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.35183",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.35183"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    },
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Complete characterization of internal-external entanglement trade-offs in two-mode Gaussian states",
  "title_text": "Complete characterization of internal-external entanglement trade-offs in two-mode Gaussian states",
  "type": "preprint",
  "updated_at": "2026-11-04T15:20:50Z",
  "url": "https://research.draconitic.com/paper/dq5049f0q0wga",
  "venue": "arXiv",
  "versions": []
}