dorsal/arxiv
View SchemaFidelity of Quantum Interferometers
| Authors | Thomas B. Bahder, Paul A. Lopata |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0602123 |
| URL | https://arxiv.org/abs/quant-ph/0602123 |
| DOI | 10.1103/PhysRevA.74.051801 |
Abstract
For a generic interferometer, the conditional probability density distribution, $p(\phi|m)$, for the phase $\phi$ given measurement outcome $m$, will generally have multiple peaks. Therefore, the phase sensitivity of an interferometer cannot be adequately characterized by the standard deviation, such as $\Delta\phi\sim 1/\sqrt{N}$ (the standard limit), or $\Delta\phi\sim 1/N$ (the Heisenberg limit). We propose an alternative measure of phase sensitivity--the fidelity of an interferometer--defined as the Shannon mutual information between the phase shift $\phi$\ and the measurement outcomes $m$. As an example application of interferometer fidelity, we consider a generic optical Mach-Zehnder interferometer, used as a sensor of a classical field. We find the surprising result that an entangled {\it N00N} state input leads to a lower fidelity than a Fock state input, for the same photon number.
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"abstract": "For a generic interferometer, the conditional probability density\ndistribution, $p(\\phi|m)$, for the phase $\\phi$ given measurement outcome $m$,\nwill generally have multiple peaks. Therefore, the phase sensitivity of an\ninterferometer cannot be adequately characterized by the standard deviation,\nsuch as $\\Delta\\phi\\sim 1/\\sqrt{N}$ (the standard limit), or $\\Delta\\phi\\sim\n1/N$ (the Heisenberg limit). We propose an alternative measure of phase\nsensitivity--the fidelity of an interferometer--defined as the Shannon mutual\ninformation between the phase shift $\\phi$\\ and the measurement outcomes $m$.\nAs an example application of interferometer fidelity, we consider a generic\noptical Mach-Zehnder interferometer, used as a sensor of a classical field. We\nfind the surprising result that an entangled {\\it N00N} state input leads to a\nlower fidelity than a Fock state input, for the same photon number.",
"arxiv_id": "quant-ph/0602123",
"authors": [
"Thomas B. Bahder",
"Paul A. Lopata"
],
"categories": [
"quant-ph"
],
"doi": "10.1103/PhysRevA.74.051801",
"title": "Fidelity of Quantum Interferometers",
"url": "https://arxiv.org/abs/quant-ph/0602123"
},
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