{
  "abstract": "Exceptional points (EPs) are usually introduced as defective degeneracies of non-Hermitian Hamiltonians and, in fully open quantum dynamics, of Liouvillian generators. Here we formulate an operational theory of exceptional points that does not invoke a Hamiltonian or a master equation. The primitive dynamical object is a completely positive trace-preserving (CPTP) quantum channel $Φ$, applied an integer number $n$ of times, while physical data are probabilities $p_n^{\\mathbf A}(x|ρ)$ associated with states $ρ$ and observables $\\mathbf A$ having measurements results $x$. We define exceptional channels through nontrivial Jordan chains of $Φ$ and show that a Jordan block of order $m$ generates discrete polynomial-exponential terms with maximal degree $m-1$. This places the physics of exceptional points in contact with what can be directly measured in experiments.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.13622",
  "author_total": 1,
  "authors": [
    {
      "name": "Paulo A. Brandão"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4656nfqq6daek.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.13622",
  "fulltext_url": null,
  "id": "4656nfqq6daek",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.13622",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "3107|Quantum Mechanics and Non-Hermitian Physics"
    ]
  ],
  "openalex": "W7221566890",
  "pdf_url": "https://arxiv.org/pdf/2610.13622",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-09",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4656nfqq6daek.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:28:36Z",
      "native_id": "2610.13622",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.13622"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Operational signatures of exceptional quantum channels",
  "title_text": "Operational signatures of exceptional quantum channels",
  "type": "preprint",
  "updated_at": "2026-10-30T12:28:36Z",
  "url": "https://research.draconitic.com/paper/4656nfqq6daek",
  "venue": "arXiv",
  "versions": []
}