{
  "abstract": "The vast majority of cosmological simulations employ periodic boundary conditions to achieve statistical homogeneity and to mimic the infinite spatial extent of our Universe. In a cubic periodic domain the Green function breaks full rotational invariance and introduces a geometry-induced anisotropy in the gravitational interaction. We quantify how this intrinsic anisotropy affects cosmic structure growth and investigate the extent to which it biases the commonly used large-scale structure and halo-based observables in dark-matter-only simulations. We analyse an ensemble of 498 cosmological dark-matter-only $N$-body simulations in cubic $T^3$ topological manifolds, evolved to $z=0$, spanning box sizes from $L=6.25\\,\\mathrm{Mpc}$ to $L=100\\,\\mathrm{Mpc}$ at fixed mass and force resolution. We compare anisotropy-sensitive statistics across the suite, including the matter power spectrum, halo abundance, merger histories, shapes and alignments, and filament orientations. Finite periodic boundaries imprint orientation-dependent signatures aligned with the box geometry. These signatures propagate beyond the largest modes and can induce systematic shifts in both field-level and halo-level statistics. The detectable effects propagate to scales much smaller than the box size. Our results demonstrate that periodic-box anisotropy is a non-negligible source of systematics for small simulation volumes, including those commonly employed in modern hydrodynamical simulations.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.08223",
  "author_total": 2,
  "authors": [
    {
      "name": "Gábor Rácz"
    },
    {
      "name": "Till Sawala"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1bhgc08e62wad.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.08223",
  "fulltext_url": null,
  "id": "1bhgc08e62wad",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.08223",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.CO"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.08223",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1bhgc08e62wad.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T18:21:30Z",
      "native_id": "2611.08223",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.08223"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    }
  ],
  "title": "The box within the Universe: anisotropies in periodic cosmological simulations I. Dark-matter-only simulations",
  "title_text": "The box within the Universe: anisotropies in periodic cosmological simulations I. Dark-matter-only simulations",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:41Z",
  "url": "https://research.draconitic.com/paper/1bhgc08e62wad",
  "venue": "arXiv",
  "versions": []
}