{
  "abstract": "Phantom-divide crossing is studied in spatially flat cosmologies with standard Friedmann equations, separately conserved holographic dark energy and a barotropic fluid, and the future event horizon as the infrared cutoff. The horizon entropy and dark-energy density are prescribed by $ S_h=S_{\\mathrm{BH}}F(L) $ and $ ρ_X\\propto F(L)/L^2 $, where $ F(L) $ is smooth, positive and single-valued, with $ χ=\\mathrm{d}\\ln F/\\mathrm{d}\\ln L $. For $ w_b>-1 $, $ 0<Ω_X<1 $ and $ χ<2 $ along the trajectory, at most one phantom-divide crossing is possible. If a crossing occurs, dark energy passes from the quintessence regime into the phantom regime at a maximum of the horizon radius. The crossing kinematics determines the local entropy-scaling dimension and the sign of the local Chevallier-Polarski-Linder coefficient. Integrating the locally prescribed scale-dependent Barrow exponent reconstructs the Barrow-Tsallis entropy function. A necessary and sufficient event-horizon consistency criterion selects admissible solutions, whose late-time asymptotics include de Sitter states, Type III and Big Rip singularities, and accelerated power-law expansion under the corresponding parameter conditions. A numerical comparison with a constant Barrow exponent distinguishes the occurrence of a crossing from the effect of exponent variation on late-time evolution. With an adiabatic barotropic fluid, additive total entropy and an equilibrium Gibbs relation for dark energy, the generalized second law fails at the kinematic crossing for positive barotropic-fluid entropy and finite nonzero dark-energy temperature. The divergence of $ c_a^2 $ shows that the purely barotropic adiabatic description of perturbations breaks down. This divergence alone does not establish physical instability.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.26089",
  "author_total": 1,
  "authors": [
    {
      "name": "D. A. Yerokhin"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5znsar8hnjwkp.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.26089",
  "fulltext_url": null,
  "id": "5znsar8hnjwkp",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.26089",
  "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",
      "astro-ph.CO"
    ],
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7171765695",
  "pdf_url": "https://arxiv.org/pdf/2607.26089",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5znsar8hnjwkp.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:06Z",
      "native_id": "2607.26089",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.26089"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Phantom-Divide Crossing in Barrow-Tsallis Holographic Dark Energy with a Scale-Dependent Barrow Exponent",
  "title_text": "Phantom-Divide Crossing in Barrow-Tsallis Holographic Dark Energy with a Scale-Dependent Barrow Exponent",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:06Z",
  "url": "https://research.draconitic.com/paper/5znsar8hnjwkp",
  "venue": "arXiv",
  "versions": []
}