{
  "abstract": "Recent experiments have sparked interest on the ground-state properties and on the excitation spectrum of the spin-$1/2$ triangular XXZ model with strong Ising-like anisotropy. In this work, we introduce and analyze a ``projected'' coherent-state approximation to the model, constructed by projecting spin-product states onto the low-energy configurations of the triangular Ising antiferromagnet. Within this approximation, we discuss the structure of the ground-state ordering and the magnetization curve under a longitudinal field. We then discuss the excitation spectrum by linearizing equations of motion deriving from a time-dependent variational principle. This leads to a natural description of spin-wave-like excitations within the strongly constrained Hilbert space. At zero field, the variational approximation leads to a very flat landscape of quasi-degenerate states, which results in a low-energy pseudo-Goldstone mode in the excitation spectrum. We compare our results to experimental measurements on the cobaltite K$_{2}$Co(SeO$_{3}$)$_{2}$ (KCSO). Our approximation leads to a dramatic improvement as compared to linear spin-wave theory. However, there remain deviations in the value of the pseudo-Goldstone gap and in the dispersion near $M$ points at low field.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.36140",
  "author_total": 2,
  "authors": [
    {
      "name": "Achille Mauri"
    },
    {
      "name": "Frédéric Mila"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7qt36477c5s7y.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.36140",
  "fulltext_url": null,
  "id": "7qt36477c5s7y",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.36140",
  "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.str-el"
    ],
    [
      "openalex",
      "3104|Advanced Condensed Matter Physics"
    ]
  ],
  "openalex": "W7214965433",
  "pdf_url": "https://arxiv.org/pdf/2609.36140",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7qt36477c5s7y.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:31Z",
      "native_id": "2609.36140",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.36140"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.str-el",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Magnetic excitations of the strongly-anisotropic triangular XXZ model: a projected spin-product state approach",
  "title_text": "Magnetic excitations of the strongly-anisotropic triangular XXZ model: a projected spin-product state approach",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:31Z",
  "url": "https://research.draconitic.com/paper/7qt36477c5s7y",
  "venue": "arXiv",
  "versions": []
}