{
  "id": "1411.6364",
  "version": "v1",
  "published": "2014-11-24T07:14:21.000Z",
  "updated": "2014-11-24T07:14:21.000Z",
  "title": "Exceptional points for parameter estimation in open quantum systems: Analysis of the Bloch equations",
  "authors": [
    "Morag Am-Shallem",
    "Ronnie Kosloff",
    "Nimrod Moiseyev"
  ],
  "comment": "16 pages, 4 figures",
  "categories": [
    "quant-ph",
    "physics.atom-ph",
    "physics.optics"
  ],
  "abstract": "The dynamics of open quantum systems is typically described by a quantum dynamical semigroup generator ${\\cal L}$. The eigenvalues of ${\\cal L}$ are complex, reflecting unitary as well as dissipative dynamics. For certain values of parameters defining ${\\cal L}$, non-hermitian degeneracies emerge, i.e. exceptional points ($EP$). We study the implications of such points in the open system dynamics of a two-level-system described by the Bloch equation. This open system has become the paradigm of diverse fields in physics, from NMR to quantum information and elementary particles. We find as a function of detuning and driving amplitude a continuous line of exceptional points merging into two cusps of triple degeneracy. The dynamical signature of these $EP$ points is a unique time evolution. This unique feature can be employed experimentally to locate the $EP$ points and thereby to determine the intrinsic system parameters for any desired accuracy.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-11-24T07:14:21.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "open quantum systems",
      "exceptional points",
      "bloch equation",
      "parameter estimation",
      "non-hermitian degeneracies emerge"
    ],
    "publication": {
      "doi": "10.1088/1367-2630/17/11/113036",
      "journal": "New Journal of Physics",
      "year": 2015,
      "month": "Nov",
      "volume": 17,
      "number": 11,
      "pages": 113036
    },
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015NJPh...17k3036A"
    }
  }
}