{
  "abstract": "Observations of the Epoch of Reionization (EoR) provide key insights into the nature of the first luminous sources and the thermal state of the intergalactic medium (IGM). Cross-correlations between the kinetic Sunyaev--Zel'dovich (kSZ) effect and neutral hydrogen (HI) 21-cm emission offer a promising probe of this era, sensitive to both the ionization and thermal histories of the early Universe. We investigate the cross-correlation of the squared kSZ field with the squared 21-cm intensity-mapping field ($\\mathrm{kSZ}^{2}\\times21\\mathrm{cm}^{2}$) over $z\\simeq9$--$16$, focusing on the impact of spatial fluctuations in the HI spin temperature. This higher-order statistic avoids line-of-sight cancellations in the kSZ signal, while squaring the 21-cm field enables non-vanishing correlations with pairs of equal and opposite high-$k_\\parallel$ modes accessible outside the foreground wedge. We forecast the cumulative signal-to-noise ratio ($\\mathrm{S/N}$) for several combinations of 21-cm and CMB experiments, including realistic instrumental noise. For a fiducial heating history and an optimistic foreground-avoidance scenario ($k_\\parallel\\leq0.1\\,h\\,\\mathrm{Mpc}^{-1}$), we find $\\mathrm{S/N}\\simeq5.89$ for SKA-Low AA$^\\ast\\times$CMB-HD and $\\simeq3.62$ for HERA$\\times$CMB-HD. If the foreground wedge extends to the horizon, these decrease to $2.94$ and $2.85$, respectively. Our results demonstrate that $\\mathrm{kSZ}^{2}\\times21\\mathrm{cm}^{2}$ is sensitive to the thermal evolution of the IGM as well as its ionization structure, providing complementary constraints on the high-redshift thermal and reionization histories.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.03527",
  "author_total": 5,
  "authors": [
    {
      "name": "Wen-Qing Guo"
    },
    {
      "name": "Yin-Zhe Ma"
    },
    {
      "name": "Adam Lidz"
    },
    {
      "name": "Steven Murray"
    },
    {
      "name": "Hemanth Potluri"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2e6zx5cfj8qrg.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.03527",
  "fulltext_url": null,
  "id": "2e6zx5cfj8qrg",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.03527",
  "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"
    ],
    [
      "openalex",
      "3103|Radio Astronomy Observations and Technology"
    ]
  ],
  "openalex": "W7220460623",
  "pdf_url": "https://arxiv.org/pdf/2610.03527",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2e6zx5cfj8qrg.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:45Z",
      "native_id": "2610.03527",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.03527"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    }
  ],
  "title": "Probing Early Phases of the Epoch of Reionization with the $\\mathrm{kSZ}^{2}\\times21\\,\\mathrm{cm}^{2}$ Cross-Correlation",
  "title_text": "Probing Early Phases of the Epoch of Reionization with the kSZ^2×21 cm^2 Cross-Correlation",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:45Z",
  "url": "https://research.draconitic.com/paper/2e6zx5cfj8qrg",
  "venue": "arXiv",
  "versions": []
}