{
  "abstract": "Synthetic lattices built from hybrid qubit-oscillator systems provide a platform for exploring topology, with multiple physical degrees of freedom enabling control over lattice geometry. A single spin-oscillator pair, described by the quantum Rabi model, provides a minimal system supporting a topological defect state on a lattice formed from the oscillator's infinite ladder of number states. However, the realization of the defect state and its robustness remain experimentally unexplored. Here we realize a topological defect state of the quantum Rabi model in a single trapped $^{171}\\mathrm{Yb}^{+}$ ion. As a coupling phase varies, reconstructed phase-space distributions yield centroid trajectories with windings of one and zero in two regimes, linking discrete-lattice topology to the geometry of the oscillator's continuous position-momentum space. The measured spin response to drive-amplitude modulation relates the stability of spin polarization to energy gaps and allowed transitions. Together, these results establish a minimal quantum system for realizing and probing topological defect states.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.34389",
  "author_total": 6,
  "authors": [
    {
      "name": "Kyungmin Lee"
    },
    {
      "name": "Jiyong Kang"
    },
    {
      "name": "Sunkyu Yu"
    },
    {
      "name": "Jaehun You"
    },
    {
      "name": "Wonhyeong Choi"
    },
    {
      "name": "Taehyun Kim"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6jc1hy358swm3.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.34389",
  "fulltext_url": null,
  "id": "6jc1hy358swm3",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.34389",
  "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",
      "quant-ph"
    ],
    [
      "openalex",
      "3107|Strong Light-Matter Interactions"
    ]
  ],
  "openalex": "W7214726227",
  "pdf_url": "https://arxiv.org/pdf/2609.34389",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6jc1hy358swm3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:01Z",
      "native_id": "2609.34389",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.34389"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Observation of a topological defect state in the quantum Rabi model",
  "title_text": "Observation of a topological defect state in the quantum Rabi model",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:01Z",
  "url": "https://research.draconitic.com/paper/6jc1hy358swm3",
  "venue": "arXiv",
  "versions": []
}