Interconvertibility of single-rail optical qubits

We show how to convert between partially coherent superpositions of a single photon with the vacuum using linear optics and postselection based on homodyne measurements. We introduce a generalized quantum efficiency for such states and show that any conversion that decreases this quantity is possibl...

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Bibliographic Details
Published inarXiv.org
Main Authors Berry, Dominic W, Lvovsky, Alexander I, Sanders, Barry C
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 22.07.2005
Subjects
Quantum efficiency
Quantum theory
Qubits (quantum computing)
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Summary:We show how to convert between partially coherent superpositions of a single photon with the vacuum using linear optics and postselection based on homodyne measurements. We introduce a generalized quantum efficiency for such states and show that any conversion that decreases this quantity is possible. We also prove that our scheme is optimal by showing that no linear optical scheme with generalized conditional measurements, and with one single-rail qubit input can improve the generalized efficiency.
ISSN:2331-8422
DOI:10.48550/arxiv.0507216