{
  "annotation_id": "a0eef4c3-1e0d-4c04-a011-d19e1a13cc15",
  "date_created": "2026-03-02T18:01:56.702000Z",
  "date_modified": "2026-03-02T18:01:56.702000Z",
  "file_hash": "65793957d81fe2b1e402fa1fb8a2be4d157ad114b8325b5cb80637f4874de035",
  "private": false,
  "record": {
    "abstract": "The discovery of entangled quantum states from which one cannot distill pure\nentanglement constitutes a fundamental recent advance in the field of quantum\ninformation. Such bipartite bound-entangled (BE) quantum states \\emph{could}\nfall into two distinct categories: (1) Inseparable states with positive partial\ntransposition (PPT), and (2) States with negative partial transposition (NPT).\nWhile the existence of PPT BE states has been confirmed, \\emph{only one} class\nof \\emph{conjectured} NPT BE states has been discovered so far. We provide\nexplicit constructions of a variety of multi-copy undistillable NPT states, and\nconjecture that they constitute families of NPT BE states. For example, we show\nthat for every pure state of Schmidt rank greater than or equal to three, one\ncan construct n-copy undistillable NPT states, for any $n\\geq1$. The abundance\nof such conjectured NPT BE states, we believe, considerably strengthens the\nnotion that being NPT is only a necessary condition for a state to be\ndistillable.",
    "arxiv_id": "quant-ph/0302093",
    "authors": [
      "Somshubhro Bandyopadhyay",
      "Vwani Roychowdhury"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.68.022319",
    "journal_ref": "Phys. Rev. A 68, 022319 (2003)",
    "title": "New classes of n-copy undistillable quantum states with negative partial   transposition",
    "url": "https://arxiv.org/abs/quant-ph/0302093"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "a6853174-bdee-4354-a88c-e18e724ce87d",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}