{
  "annotation_id": "55544774-8b3b-4639-a98e-1378493f7801",
  "date_created": "2026-03-02T18:01:48.941000Z",
  "date_modified": "2026-03-02T18:01:48.941000Z",
  "file_hash": "651f4aa393dd111afc411d9e66a774245d3c8cc20ac62144bc35589aaf02e74c",
  "private": false,
  "record": {
    "abstract": "We present a new protocol and two lower bounds for quantum coin flipping. In\nour protocol, no dishonest party can achieve one outcome with probability more\nthan 0.75. Then, we show that our protocol is optimal for a certain type of\nquantum protocols.\n  For arbitrary quantum protocols, we show that if a protocol achieves a bias\nof at most $\\epsilon$, it must use at least $\\Omega(\\log \\log\n\\frac{1}{\\epsilon})$ rounds of communication. This implies that the parallel\nrepetition fails for quantum coin flipping. (The bias of a protocol cannot be\narbitrarily decreased by running several copies of it in parallel.)",
    "arxiv_id": "quant-ph/0204022",
    "authors": [
      "Andris Ambainis"
    ],
    "categories": [
      "quant-ph",
      "cs.CR"
    ],
    "journal_ref": "Journal of Computer and System Sciences, 68(2): 398-416, 2004.",
    "title": "A New Protocol and Lower Bounds for Quantum Coin Flipping",
    "url": "https://arxiv.org/abs/quant-ph/0204022"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "c1b27519-7ddf-4eba-8298-263b13116ebe",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}