arXiv:0709.3867 · Physical Review A

Rapid-purification protocols for optical homodyning

Aravind Chiruvelli, Kurt A. Jacobs

Published Jan 8, 2008• 6 citations

Abstract

We present a number of rapid-purification feedback protocols for optical homodyne detection of a single optical qubit. We derive first a protocol that speeds up the rate of increase of the average purity of the system, and find that as in the equivalent protocol for a nondissipative measurement, this generates a deterministic evolution for the purity in the limit of strong feedback. We also consider two analogs of the Wiseman-Ralph rapid-purification protocol in this setting, and show that as in that protocol they speed up the average time taken to reach a fixed level of purity. We also examine how the performance of these algorithms changes with detection efficiency, being an important practical consideration.

DOI: 10.1103/physreva.77.012102

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