{
  "abstract": "It is known that a one-dimensional (1D) quantum walk gives a local space-time discretization of the massless Dirac equation with a single quasi-energy cone (no fermion doubling at low energies), keeping the fundamental symmetries (chiral and time-reversal) of the continuum theory. We show that the analogous 2D construction is fundamentally more fragile. Local two-band quantum walks can have an unpaired Dirac cone, but the protecting symmetries then cease to be ordinary on-site symmetries: They become non-symmorphic, involving half-lattice translations, and are broken by generic spatial inhomogeneities. In particular, we demonstrate that the 2D Dirac quantum walk based on the Ho-Chalker network model can be gapped by potential scattering, as is evidenced by the breakdown of reflectionless Klein tunneling. The symmorphic symmetry obstruction is sharp: If we allow for couplings that are no longer strictly finite-range but decay exponentially with distance, we can construct a 2D quantum walk with a single Dirac cone and on-site chiral and time-reversal symmetries.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Phys. Rev. A 114, 042213 (2026)",
  "arxiv": "2607.05112",
  "author_total": 3,
  "authors": [
    {
      "name": "C. W. J. Beenakker"
    },
    {
      "name": "J. Sánchez Férnan"
    },
    {
      "name": "J. Tworzydło"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3fm1nq2karr06.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.05112",
  "fulltext_url": null,
  "id": "3fm1nq2karr06",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.05112",
  "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",
      "cond-mat.mes-hall"
    ],
    [
      "arxiv",
      "quant-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2607.05112",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-20",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3fm1nq2karr06.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2607.05112",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.05112"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mes-hall",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Fragile single-cone Dirac quantum walks in two dimensions",
  "title_text": "Fragile single-cone Dirac quantum walks in two dimensions",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:41Z",
  "url": "https://research.draconitic.com/paper/3fm1nq2karr06",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1103/cdkh-h1jx",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}