{
  "abstract": "We study odd-parity perturbations of Reissner-Nordström black holes in dynamical Chern-Simons gravity. The dCS action is parity invariant because $\\vartheta\\,{}^{*}RR$ is the product of two pseudoscalars; nevertheless, the pseudoscalar perturbation has odd parity and enters only the axial sector at linear order and so lifts the axial--polar isospectrality of general relativity. We derive the finite-charge couplings between the pseudoscalar and the axial gravitational and electromagnetic perturbations directly from the linearized field equations. Both directions are governed by the radial kernel $(Mr-Q^2)Δ/r^8$, and at nonzero charge the pseudoscalar couples to $Ψ+χΨ_e$, with $χ=2Q/[r\\sqrt{(l-1)(l+2)}]$. After diagonalizing the Einstein--Maxwell sector, we compute branch-resolved quasinormal-mode shifts with exterior complex scaling for the photon-sphere modes and Frobenius shooting for the near-extremal zero-damping modes. For the Schwarzschild $l=2$ fundamental mode we obtain $β\\,δω=-0.7733-0.3946\\,i$ (units $M=α=1$). Off resonance, the gravitational-led shift scales as $ζ\\,l^3$ at $Q=0$ but as $ζ\\,l^2/Q$ at fixed nonzero charge and large $l$. The electromagnetic-led branch becomes exactly degenerate with the pseudoscalar mode at $Q_c=2M\\sqrt{l(l+1)+1}/[l(l+1)+2]$, where the pseudoscalar potential coincides with the polar partner of the electromagnetic-led potential; there the breaking is $\\mathcal{O}(\\sqrtζ)$, $M|Δω|\\simeq2.4\\sqrtζ$ for $l=2$, and the shift reverses sign across $Q_c$. Near extremality the photon-sphere shifts remain finite, whereas the non-degenerate fundamental gravitational-led zero-damping mode is suppressed, $δω/ω\\simeq6.0\\times10^{3}\\,ζ\\,(1-Q^2/M^2)$ for $l=2$.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.38742",
  "author_total": 1,
  "authors": [
    {
      "name": "Abhishek Rout"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/817xyx9yb4zec.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.38742",
  "fulltext_url": null,
  "id": "817xyx9yb4zec",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.38742",
  "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",
      "gr-qc"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.38742",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/817xyx9yb4zec.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:23Z",
      "native_id": "2610.38742",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.38742"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Isospectrality breaking in the axial quasinormal modes of Reissner-Nordström black holes in dynamical Chern-Simons gravity",
  "title_text": "Isospectrality breaking in the axial quasinormal modes of Reissner-Nordström black holes in dynamical Chern-Simons gravity",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:45Z",
  "url": "https://research.draconitic.com/paper/817xyx9yb4zec",
  "venue": "arXiv",
  "versions": []
}