{
  "abstract": "We study the bosonic type IIB (IKKT) matrix model and the fate of the D-instanton positions $p^{(i)}_μ$, the diagonal components of the $d$ Hermitian matrices, whose one-loop effective potential infamously drives them to a single point. We show that this collapse is an artifact of the leading (one-loop) truncation, while the actual non-collapse of the $p^{(i)}_μ$ is a nonperturbative effect: it is invisible at one loop but already present in the exact (all-loop) two-body interaction. Since the two-body sector of the $N\\times N$ model factorizes into copies of $N=2$, this interaction is captured exactly by the $\\mathrm{U}(2)$ model, and we find that the two D-instantons do not collapse onto each other. To set up the computation, we gauge-fix the $\\text{U}(N)$ symmetry in a way that keeps the diagonal and off-diagonal sectors distinct, and we handle the residual $\\mathrm{U}(1)^N$ symmetry with an auxiliary-ghost BRST construction. This construction generates a new ghost four-leg vertex; the resulting Faddeev-Popov determinant admits a systematic large-separation expansion that organizes the effective potential into a many-body decomposition, separating the interaction into two-body, three-body, and higher-body contributions. The exact $N=2$ partition function is finite at finite separation; its naive Lorenz-gauge form develops a negative region at separations of order one, which we trace to a Gribov ambiguity of the Lorenz gauge and resolve with the maximal diagonal gauge--the classical frame containing the perturbative vacuum--where the short-distance force is finite and repulsive, so that the two-body potential develops a stable minimum at finite separation. These results are consistent with a stable, non-collapsed distribution of the $p^{(i)}_μ$; establishing the detailed distribution and full $N$-body non-collapse requires the higher-body potentials and is left to future work.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.09598",
  "author_total": 4,
  "authors": [
    {
      "name": "Yu-An Chen"
    },
    {
      "name": "Hikaru Kawai"
    },
    {
      "name": "Henry Liao"
    },
    {
      "name": "Cheng-Tsung Wang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/31756k2jj1szr.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.09598",
  "fulltext_url": null,
  "id": "31756k2jj1szr",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.09598",
  "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",
      "hep-th"
    ],
    [
      "openalex",
      "3106|Black Holes and Theoretical Physics"
    ]
  ],
  "openalex": "W7202215744",
  "pdf_url": "https://arxiv.org/pdf/2608.09598",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/31756k2jj1szr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:56Z",
      "native_id": "2608.09598",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.09598"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-th",
      "subfield": "high-energy"
    }
  ],
  "title": "Nonperturbative Stabilization of D-Instantons in the Bosonic IIB Matrix Model",
  "title_text": "Nonperturbative Stabilization of D-Instantons in the Bosonic IIB Matrix Model",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:56Z",
  "url": "https://research.draconitic.com/paper/31756k2jj1szr",
  "venue": "arXiv",
  "versions": []
}