{
  "abstract": "We study the Loschmidt echo in a system of N non-interacting spinless lattice fermions released from a double-domain-wall initial state. In the large-N limit, the return probability is characterized by a large-deviation rate function known as the dynamical free energy. The Loschmidt echo is dominated by a complex instanton configuration, and the dynamical free energy develops a logarithmic singularity at the dynamical quantum phase transition. We obtain analytical results in the short-time and long-time regimes and support them with numerical computations. We show that the transition can be understood as a topological change of the dominant instanton configuration, analogous to the emergence of a cut in random matrix theory. We further show that post-selection can drive the system through two successive DQPTs, associated with successive topological changes of the dominant instanton configuration in complex time.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.18208",
  "author_total": 6,
  "authors": [
    {
      "name": "Yasser Bezzaz"
    },
    {
      "name": "Dimitri M Gangardt"
    },
    {
      "name": "Pavel L Krapivsky"
    },
    {
      "name": "Jean-Marc Luck"
    },
    {
      "name": "Kirone Mallick"
    },
    {
      "name": "Sylvain Prolhac"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/asg74ycd7m7n8.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.18208",
  "fulltext_url": null,
  "id": "asg74ycd7m7n8",
  "issns": [],
  "landing_url": "https://hal.science/hal-05781697v1",
  "language": "en",
  "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",
      "cond-mat.stat-mech"
    ],
    [
      "hal",
      "0.phys"
    ],
    [
      "hal",
      "1.phys.cond"
    ],
    [
      "openalex",
      "3107|Quantum many-body systems"
    ]
  ],
  "openalex": "W7213523939",
  "pdf_url": "https://arxiv.org/pdf/2609.18208",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/asg74ycd7m7n8.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:49Z",
      "native_id": "hal-05781697",
      "source": "hal",
      "url": "https://hal.science/hal-05781697v1"
    },
    {
      "first_seen": "2026-10-30T12:22:01Z",
      "native_id": "2609.18208",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.18208"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "hal:1.phys.cond",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.stat-mech",
      "subfield": "statistical-nonlinear"
    }
  ],
  "title": "Logarithmic singularity in a dynamical quantum phase transition for free fermions",
  "title_text": "Logarithmic singularity in a dynamical quantum phase transition for free fermions",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:01Z",
  "url": "https://research.draconitic.com/paper/asg74ycd7m7n8",
  "venue": "HAL",
  "versions": []
}