{
  "abstract": "Recently, the James Webb Space Telescope (JWST) collaboration has found the unexpectedly large abundance of massive galaxies with stellar masses of $\\sim 10^{10}~M_{\\odot}$ at high redshifts $z \\simeq 6.5 - 9$ compared with the prediction of the standard $Λ$CDM model. As a possible solution to the tension, we consider a blue-tilted spectrum of density perturbations with a positive running. We find that, for $α_s \\simeq 0.02$ and $β_s \\simeq 0.02$, a joint analysis with CMB observations shows that the tension can be resolved at the 1$σ$ confidence level. Such a blue-tilted spectrum is also plausible from the perspective for formations of primordial black holes on much smaller scales in the early Universe.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Phys.Rev.D 114 (2026) 6, 063537",
  "arxiv": "2605.22161",
  "author_total": 7,
  "authors": [
    {
      "name": "Mikage U. Kobayashi"
    },
    {
      "name": "Gen Chiaki"
    },
    {
      "name": "Kazutaka Kimura"
    },
    {
      "name": "Kazuyuki Akitsu"
    },
    {
      "name": "Kazunori Kohri"
    },
    {
      "name": "Tomo Takahashi"
    },
    {
      "name": "Kazuyuki Omukai"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/atc10vn2z7bpe.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.22161",
  "fulltext_url": null,
  "id": "atc10vn2z7bpe",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.22161",
  "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",
      "astro-ph.GA"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7162126571",
  "pdf_url": "https://arxiv.org/pdf/2605.22161",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/atc10vn2z7bpe.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:31Z",
      "native_id": "2605.22161",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.22161"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Blue-tilted spectral running and the JWST early galaxy tension",
  "title_text": "Blue-tilted spectral running and the JWST early galaxy tension",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:31Z",
  "url": "https://research.draconitic.com/paper/atc10vn2z7bpe",
  "venue": "arXiv",
  "versions": []
}