{
  "abstract": "In this manuscript, we analyze the dynamics of a model in which two spin-1/2 systems are each coupled noncommutingly to a static environmental field and to a self-Hamiltonian, while also being mutually coupled through a $σ_y^{(1)}σ_y^{(2)}$ interaction. By constructing an exact solution that exploits parity symmetry, and by applying the stationary-phase approximation (the saddle-point method) in the continuum limit of the environmental field, we show that coherence associated with the ordinary isolated stationary point decays as $t^{-1}$, whereas, under the resonance condition at which the local effective fields of the two spins cancel each other, only the coherence between a pair of maximally entangled, Bell-type states- the eigenbasis of the inter-system coupling-survives, decaying via the anomalously slow power law $t^{-1/2}$. Through a comparison with the pointer-basis theory of W. H. Zurek and coworkers (the 1981 and 2005 models), we further reveal a mechanism not reducible to local coupling: in this system, the pointer observable is determined not by the individual system-environment couplings but by a statistical resonance condition between the two environments.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.18641",
  "author_total": 1,
  "authors": [
    {
      "name": "Kentaro Urasaki"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/aw43cbfty55qs.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.18641",
  "fulltext_url": null,
  "id": "aw43cbfty55qs",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.18641",
  "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",
      "quant-ph"
    ],
    [
      "openalex",
      "3107|Quantum Mechanics and Applications"
    ]
  ],
  "openalex": "W7213526184",
  "pdf_url": "https://arxiv.org/pdf/2609.18641",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-17",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/aw43cbfty55qs.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:19Z",
      "native_id": "2609.18641",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.18641"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Resonance-Protected Pointer States: Stationary-Phase Analysis of Entanglement in an Environment-Coupled Two-Spin System",
  "title_text": "Resonance-Protected Pointer States: Stationary-Phase Analysis of Entanglement in an Environment-Coupled Two-Spin System",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:19Z",
  "url": "https://research.draconitic.com/paper/aw43cbfty55qs",
  "venue": "arXiv",
  "versions": []
}