{
  "annotation_id": "a01feea4-06c6-45e1-9a58-e03b46997958",
  "date_created": "2026-03-02T18:02:19.424000Z",
  "date_modified": "2026-03-02T18:02:19.424000Z",
  "file_hash": "722e16d60e731a3f68ccad67a80ff44101216ac7baf13b6ac9aaa54e5d2ee18c",
  "private": false,
  "record": {
    "abstract": "We analyze how a maximally entangled state of two-qubits (e.g., the singlet\n$\\psi_s$) is affected by action of local channels described by completely\npositive maps $\\cE$ . We analyze the concurrence and the purity of states\n$\\varrho_\\cE=\\cE\\otimes\\cI[\\psi_s]$.Using the concurrence-{\\it vs}-purity phase\ndiagram we characterize local channels $\\cE$ by their action on the singlet\nstate $\\psi_s$. We specify a region of the concurrence-{\\it vs.}-purity diagram\nthat is achievable from the singlet state via the action of unital channels. We\nshow that even most general (including non-unital) local channels acting just\non a single qubit of the original singlet state cannot generate the maximally\nentangled mixed states (MEMS). We study in detail various time evolutions of\nthe original singlet state induced by local Markovian semigroups. We show that\nthe decoherence process is represented in the concurrence-{\\it vs.}-purity\ndiagram by a line that forms the lower bound of the achievable region for\nunital maps. On the other hand, the depolarization process is represented by a\nline that forms the upper bound of the region of maps induced by unital maps.",
    "arxiv_id": "quant-ph/0508106",
    "authors": [
      "Mario Ziman",
      "Vladimir Buzek"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.72.052325",
    "title": "Concurrence vs. purity: Influence of local channels on Bell states of   two qubits",
    "url": "https://arxiv.org/abs/quant-ph/0508106"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "abf98ece-ea35-4969-a74d-4fcce319d678",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}