{
  "annotation_id": "dc9b2664-3c26-4019-bbf5-407159387f12",
  "date_created": "2026-03-02T18:02:13.578000Z",
  "date_modified": "2026-03-02T18:02:13.578000Z",
  "file_hash": "06aacf69e666adcce50c75b942cf1fe5d27d1aba7e4c7139a73ae074bfd03c9f",
  "private": false,
  "record": {
    "abstract": "We propose a new approach to the measurement of a single spin state, based on\nnuclear magnetic resonance (NMR) techniques and inspired by the coherent\ncontrol over many-body systems envisaged by Quantum Information Processing\n(QIP). A single target spin is coupled via the natural magnetic dipolar\ninteraction to a large ensemble of spins. Applying external radio frequency\n(rf) pulses, we can control the evolution of the system so that the spin\nensemble reaches one of two orthogonal states whose collective properties\ndiffer depending on the state of the target spin and are easily measured. We\nfirst describe this measurement process using QIP gates; then we show how\nequivalent schemes can be defined in terms of the Hamiltonian of the spin\nsystem and thus implemented under conditions of real control, using well\nestablished NMR techniques. We demonstrate this method with a proof of\nprinciple experiment in ensemble liquid state NMR and simulations for small\nspin systems.",
    "arxiv_id": "quant-ph/0411128",
    "authors": [
      "Paola Cappellaro",
      "Joseph Emerson",
      "Nicolas Boulant",
      "Chandrasekhar Ramanathan",
      "Seth Lloyd",
      "David G. Cory"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.94.020502",
    "journal_ref": "Phys. Rev. Lett. 94, 020502 (2005)",
    "title": "Entanglement Assisted Metrology",
    "url": "https://arxiv.org/abs/quant-ph/0411128"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "e1233535-946a-4835-991e-78451e1efba5",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}