{
  "abstract": "Mixed quantum states can exhibit unconventional forms of symmetry breaking without pure-state counterparts. A prominent example is strong-to-weak spontaneous symmetry breaking (SW-SSB), which cannot be diagnosed by observables linear in the density matrix. Here, we experimentally resolve finite-size critical signatures of SW-SSB transitions on a superconducting quantum processor. We develop a measurement protocol that combines quantum measurements with classical processing based on the known dephasing channel to reconstruct nonlinear mixed-state correlators. Using only two measurement settings, the protocol reconstructs fidelity, Rényi-2, and linear correlators, as well as string observables. Applying this approach to matrix-product states subjected to power-law-correlated dephasing, we observe finite-size crossings and scaling collapses in nonlinear correlators, accompanied by decaying linear correlations. We further map the estimated SW-SSB transition points across initial-state and channel parameters. Measurements of linear and Rényi-2 string observables further reveal signatures of mixed-state symmetry-protected topological (SPT) phases, with a nonlinear string-order crossover aligned with an independently estimated SW-SSB transition point. Our results establish a quantum-classical approach to probing SW-SSB critical behavior and mixed-state SPT order.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.26229",
  "author_total": 7,
  "authors": [
    {
      "name": "Zhi-Yuan Wei"
    },
    {
      "name": "Christopher Fechisin"
    },
    {
      "name": "Yu-Xin Wang"
    },
    {
      "name": "Jeet Shah"
    },
    {
      "name": "Tsung-Cheng Lu"
    },
    {
      "name": "Cheng-Ju Lin"
    },
    {
      "name": "Alexey V. Gorshkov"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bzaht1qnct3hm.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.26229",
  "fulltext_url": null,
  "id": "bzaht1qnct3hm",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.26229",
  "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 many-body systems"
    ]
  ],
  "openalex": "W7223027921",
  "pdf_url": "https://arxiv.org/pdf/2610.26229",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-19",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bzaht1qnct3hm.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2610.26229",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.26229"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Strong-to-Weak Spontaneous Symmetry Breaking Transitions on a Quantum Processor",
  "title_text": "Strong-to-Weak Spontaneous Symmetry Breaking Transitions on a Quantum Processor",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:41Z",
  "url": "https://research.draconitic.com/paper/bzaht1qnct3hm",
  "venue": "arXiv",
  "versions": []
}