Exceptional points for parameter estimation in open quantum systems: Analysis of the Bloch equations

We suggest to employ the dissipative nature of open quantum systems for the purpose of parameter estimation: 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...

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Veröffentlicht in:arXiv.org 2015-12
Hauptverfasser: Am-Shallem, Morag, Kosloff, Ronnie, Moiseyev, Nimrod
Format: Artikel
Sprache:eng
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Zusammenfassung:We suggest to employ the dissipative nature of open quantum systems for the purpose of parameter estimation: 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 (\(EP\)). The dynamical signature of these \(EP\)s corresponds to a unique time evolution. This unique feature can be employed experimentally to locate the \(EP\)s and thereby to determine the intrinsic system parameters with a high accuracy. This way we turn the disadvantage of the dissipation into an advantage. We demonstrate this method in the open system dynamics of a two-level system described by the Bloch equation, which has become the paradigm of diverse fields in physics, from NMR to quantum information and elementary particles.
ISSN:2331-8422
DOI:10.48550/arxiv.1411.6364