{
  "annotation_id": "9f9ba343-48f5-45f8-8d02-872f30e65dcf",
  "date_created": "2026-03-02T18:02:40.640000Z",
  "date_modified": "2026-03-02T18:02:40.640000Z",
  "file_hash": "52fc518fc6535d856913cf37df8e6918940cf1450566c0fef4da7089e9308c97",
  "private": false,
  "record": {
    "abstract": "We investigate means to describe the non-local properties of quantum systems\nand to test if two quantum systems are locally equivalent. For this we consider\nquantum systems that consist of several subsystems, especially multiple qubits.\nWe compute invariant polynomials, i. e., polynomial functions of the entries of\nthe density operator which are invariant under local unitary operations.\n  As an example, we consider a system of two qubits. We compute the Molien\nseries for the corresponding representation which gives information about the\nnumber of linearly independent invariants. Furthermore, we present a set of\npolynomials which generate all invariants (at least) up to degree 23. Finally,\nthe use of invariants to check whether two density operators are locally\nequivalent is demonstrated.",
    "arxiv_id": "quant-ph/9712040",
    "authors": [
      "Markus Grassl",
      "Martin Roetteler",
      "Thomas Beth"
    ],
    "categories": [
      "quant-ph",
      "cs.ET"
    ],
    "doi": "10.1103/PhysRevA.58.1833",
    "journal_ref": "Phys.Rev.A58:1833-1839,1998",
    "title": "Computing Local Invariants of Qubit Systems",
    "url": "https://arxiv.org/abs/quant-ph/9712040"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "18bed6cf-7965-406c-9b67-df280ada1919",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}