{
  "annotation_id": "6d4b6214-a9ec-42c4-a84a-344236e294c6",
  "date_created": "2026-03-02T18:02:27.449000Z",
  "date_modified": "2026-03-02T18:02:27.449000Z",
  "file_hash": "36942cf6ff09943c9fd6ec3c08746b03ecd186b7c8c0f8142c7f5a0bf7703fb7",
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  "record": {
    "abstract": "We present a Hamiltonian that can be used for amplifying the signal from a\nquantum state, enabling the measurement of a macroscopic observable to\ndetermine the state of a single spin. We prove a general mapping between this\nHamiltonian and an exchange Hamiltonian for arbitrary coupling strengths and\nlocal magnetic fields. This facilitates the use of existing schemes for perfect\nstate transfer to give perfect amplification. We further prove a link between\nthe evolution of this fixed Hamiltonian and classical Cellular Automata,\nthereby unifying previous approaches to this amplification task.\n  Finally, we show how to use the new Hamiltonian for perfect state transfer in\nthe, to date, unique scenario where total spin is not conserved during the\nevolution, and demonstrate that this yields a significantly different response\nin the presence of decoherence.",
    "arxiv_id": "quant-ph/0604137",
    "authors": [
      "A. Kay"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevLett.98.010501",
    "journal_ref": "Phys. Rev. Lett. 98, 010501 (2007)",
    "title": "State Transfer and Spin Measurement",
    "url": "https://arxiv.org/abs/quant-ph/0604137"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "ffb5f82d-9dcd-4b58-93e0-cdbeeaa2bc30",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}