{
  "abstract": "We study the critical dynamics of the quantum random-field Ising model using the nonperturbative functional renormalization group (NP-FRG). The static critical behavior is found to be controlled by the zero-temperature fixed point of the classical random-field Ising model, where both thermal and quantum fluctuations are dangerously irrelevant. Considering a family of quantum dynamical universality classes defined by a bare dynamical kernel F Λ (ω) ∼ |ω| σ , we show how this fluctuationless fixed point nevertheless controls the quantum dynamics by computing the full Matsubara-frequency dependence of the running dynamical kernel F k (ω). This is essential at zero temperature: a naive treatment of the dynamical kernel flow leads to a divergence at a finite length scale, resulting in apparent localization. In contrast, keeping the full frequency dependence of the dynamical kernel and choosing a regulator adapted to its running scale yields a controlled flow.\n\nThe resulting dynamics is of activated form, with a relaxation time given by ln τ ∼ ξ Ψ . The exponent Ψ is determined by the static RFIM fixed-point exponents and by σ. At finite temperature, the flow crosses over to the classical thermally activated scaling of the random-field Ising model.\n\nThese results provide a quantitative field-theoretic realization of the heuristic activation scenario proposed earlier for the quantum random-field model and establish a framework for analyzing the dynamics of other disordered quantum systems that may exhibit similar tentative localization-like singularities.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.31663",
  "author_total": 3,
  "authors": [
    {
      "name": "Ivan Balog"
    },
    {
      "name": "Lovro Šaravanja"
    },
    {
      "name": "Andrei Fedorenko"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/64g0pr8avfbba.bib",
  "cited_by": 0,
  "doi": null,
  "fulltext_url": null,
  "id": "64g0pr8avfbba",
  "issns": [],
  "landing_url": "https://hal.science/hal-05850775v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.phys"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://hal.science/hal-05850775/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-06-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/64g0pr8avfbba.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T12:20:53Z",
      "native_id": "hal-05850775",
      "source": "hal",
      "url": "https://hal.science/hal-05850775v1"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "hal:0.phys",
      "subfield": "general"
    }
  ],
  "title": "Activated dynamics in the quantum random field Ising model",
  "title_text": "Activated dynamics in the quantum random field Ising model",
  "type": "preprint",
  "updated_at": "2026-11-04T12:20:53Z",
  "url": "https://research.draconitic.com/paper/64g0pr8avfbba",
  "venue": "HAL",
  "versions": []
}