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arXiv · 1005.3706

Noise-Powered Probabilistic Concentration of Phase Information

Mario A. Usuga·Christian R. Mueller·Christoffer Wittmann·Petr Marek·Radim Filip·Christoph Marquardt·Gerd Leuchs·Ulrik L. Andersen
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Abstract

Phase insensitive optical amplification of an unknown quantum state is known to be a fundamentally noisy operation that inevitably adds noise to the amplified state [1 - 5]. However, this fundamental noise penalty in amplification can be circumvented by resorting to a probabilistic scheme as recently proposed and demonstrated in refs [6 - 8]. These amplifiers are based on highly non-classical resources in a complex interferometer. Here we demonstrate a probabilistic quantum amplifier beating the fundamental quantum limit utilizing a thermal noise source and a photon number subtraction scheme [9]. The experiment shows, surprisingly, that the addition of incoherent noise leads to a noiselessly amplified output state with a phase uncertainty below the uncertainty of the state prior to amplification. This amplifier might become a valuable quantum tool in future quantum metrological schemes and quantum communication protocols.

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Mario A. Usuga, Christian R. Mueller, Christoffer Wittmann, Petr Marek, Radim Filip, Christoph Marquardt, Gerd Leuchs, Ulrik L. Andersen. 2010-06-07. Noise-Powered Probabilistic Concentration of Phase Information. https://doi.org/10.1038/nphys1743

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