Robustness of homodyne tomography to phase-insensitive noise |
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| Authors: | Giacomo Mauro D'ariano Nicoletta Sterpi |
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| Affiliation: | 1. Department of Electrical and Computer Engineering, Department of Physics and Astronomy , Northwestern University, Evanston , IL, 60208, USA;2. Dipartimento di Fisica ?A. Volta‘ , Via Bassi 6, 27100, Pavia, Italy;3. Dipartimento di Fisica ?A. Volta‘ , Via Bassi 6, 27100, Pavia, Italy |
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| Abstract: | Abstract We study the effects of phase-insensitive noise on homodyne measurements of a radiation density matrix. We prove that this noise has an effect equivalent to a non-unit quantum efficiency at detectors. The overall effective quantum efficiency η? of the measurement is evaluated in terms of the quantum efficiency at detectors and of the average number of noise photons added to the radiation field. For pure Gaussian-displacement noise, we show that half a photon of noise is enough to prevent the homodyne measurement of the density matrix. |
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