{
  "abstract": "A bstract : We consider quantum decoherence and entropy increase in early universe cosmology. We first study decoherence in a discrete bipartite quantum system for which a single qubit gets entangled with an environment and the entropy increase is correlated with the decay of the off-diagonal terms of the reduced density matrix. We compare this system with continuous systems relevant for cosmology for which there is a natural external intervention, corresponding to the time-dependent separation between the sub- and super-horizon infla-tionary fluctuations. We find, in this case, that the off-diagonal terms of the density matrix, in a field basis, do not decay as sometimes assumed in cosmological set-ups. Nevertheless, following a recent treatment in terms of open Effective Field Theories (EFTs), we compute the entanglement entropy for a Gaussian state and show that it actually increases monotonically ( $$\\dot{S}>0$$ ) during the accelerated phases ( $$\\ddot{a}>0$$ with a ( t ) the scale factor). We generalise this result to include non-Gaussian states and briefly discuss the relevance of computing the von Neumann entropy as compared to the thermodynamic entropy.",
  "abstract_shown": true,
  "affiliations": [
    "Imperial College London",
    "Universidad de Chile",
    "University of Colorado",
    "New York University Abu Dhabi",
    "DAMTP University of Cambridge"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Sebastián Céspedes",
      "orcid": "0000-0002-2042-5001"
    },
    {
      "affs": [
        2
      ],
      "name": "Senarath de Alwis",
      "orcid": "0000-0002-6907-947X"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "Fernando Quevedo",
      "orcid": "0000-0002-7810-3662"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/aacyndmtk4sad.bib",
  "cited_by": 0,
  "doi": "10.1007/jhep10(2026)176",
  "fulltext_url": null,
  "id": "aacyndmtk4sad",
  "issns": [
    "1029-8479"
  ],
  "landing_url": "https://link.springer.com/article/10.1007/JHEP10(2026)176",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W4415057881",
  "pdf_url": "https://link.springer.com/content/pdf/10.1007/JHEP10(2026)176.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-15",
  "publisher": "Springer Science and Business Media LLC",
  "ris": "https://research.draconitic.com/paper/aacyndmtk4sad.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:01Z",
      "native_id": "10.1007/jhep10(2026)176",
      "source": "crossref",
      "url": "https://link.springer.com/article/10.1007/JHEP10(2026)176"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Cosmology and Gravitation Theories",
      "subfield": "cosmology"
    }
  ],
  "title": "Cosmology, decoherence and the second law",
  "title_text": "Cosmology, decoherence and the second law",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:01Z",
  "url": "https://research.draconitic.com/paper/aacyndmtk4sad",
  "venue": "Journal of High Energy Physics",
  "versions": []
}