{
  "abstract": "We show that assuming the existence of homomorphic encryption, parallel repetition of all interactive arguments (after being run under homomorphic encryption) reduces the soundness error at a tight exponential rate even in the post-quantum setting. Moreover, we generalize this result to hold for threshold verifiers, where the parallel repeated verifier accepts if and only if at least $t$ of the executions are accepted (for some threshold $t$). Prior to this work, these results were known only when the cheating prover was assumed to be classical, and it was not known how to achieve tight bounds. As a corollary, we construct the first constant-round succinct argument for $\\mathsf{QMA}$ with negligible completeness and soundness errors assuming only the existence of quantum homomorphic encryption.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.38941",
  "author_total": 4,
  "authors": [
    {
      "name": "Zvika Brakerski"
    },
    {
      "name": "Andrew Huang"
    },
    {
      "name": "Yael Tauman Kalai"
    },
    {
      "name": "Nicholas Spooner"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8p9sjz5gde79r.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.38941",
  "fulltext_url": null,
  "id": "8p9sjz5gde79r",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.38941",
  "language": null,
  "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",
      "cs.CR"
    ],
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "1702|Cryptography and Data Security"
    ]
  ],
  "openalex": "W7215072431",
  "pdf_url": "https://arxiv.org/pdf/2609.38941",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8p9sjz5gde79r.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:03Z",
      "native_id": "2609.38941",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.38941"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Tight Post-Quantum Parallel Repetition for Private-Coin Arguments",
  "title_text": "Tight Post-Quantum Parallel Repetition for Private-Coin Arguments",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:03Z",
  "url": "https://research.draconitic.com/paper/8p9sjz5gde79r",
  "venue": "arXiv",
  "versions": []
}