{
  "abstract": "We investigate the long-distance recovery of the particle-number density near a static, impermeable wall in a $d$-dimensional Galilean-invariant superfluid. Using superfluid effective field theory (EFT) on a half-space, we show that quantum phonon fluctuations produce a $z^{-(d+1)}$ tail in the smooth density profile at zero temperature, where $z$ is the distance from the wall. The tail coefficient is fixed by the bulk equation of state and is independent of microscopic wall details. At low temperature $T$, the thermal length $c_s/T$, with $c_s$ the bulk sound speed, separates the zero-temperature behavior at intermediate distances from a thermal $Tz^{-d}$ tail at larger distances for $d>1$. For $d=1$, the long-distance phonon contribution instead decays as $\\exp(-4πTz/c_s)$. The EFT applies to both Bose and Fermi superfluids, including strongly interacting Fermi gases at unitarity. We estimate the normalized tail amplitude in three dimensions across the BCS--BEC crossover using experimental sound-speed data.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.23165",
  "author_total": 1,
  "authors": [
    {
      "name": "Keisuke Fujii"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9crgajtd595vh.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.23165",
  "fulltext_url": null,
  "id": "9crgajtd595vh",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.23165",
  "language": null,
  "licence": "CC-BY-NC-SA-4.0",
  "licence_label": "CC BY-NC-SA 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-sa/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.quant-gas"
    ],
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3107|Cold Atom Physics and Bose-Einstein Condensates"
    ]
  ],
  "openalex": "W7222917246",
  "pdf_url": "https://arxiv.org/pdf/2610.23165",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9crgajtd595vh.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:32Z",
      "native_id": "2610.23165",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.23165"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.quant-gas",
      "subfield": "amo"
    },
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.quant-gas",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-th",
      "subfield": "high-energy"
    }
  ],
  "title": "Universal Long-distance Tail of Particle-number Density near a Wall in Superfluids",
  "title_text": "Universal Long-distance Tail of Particle-number Density near a Wall in Superfluids",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:28Z",
  "url": "https://research.draconitic.com/paper/9crgajtd595vh",
  "venue": "arXiv",
  "versions": []
}