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arXiv · 1301.1016

Unconditional quantum-noise suppression via measurement-based quantum feedback

Ryotaro Inoue·Shin-Ichi-Ro Tanaka·Ryo Namiki·Takahiro Sagawa·Yoshiro Takahashi
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Abstract

We demonstrate unconditional quantum-noise suppression in a collective spin system via feedback control based on quantum non-demolition measurement (QNDM). We perform shot-noise limited collective spin measurements on an ensemble of $3.7\times 10^5$ laser-cooled 171Yb atoms in their spin-1/2 ground states. Correlation between two sequential QNDMs indicates $-0.80^{+0.11}_{-0.12}\,\mathrm{dB}$ quantum noise suppression in a conditional manner. Our feedback control successfully converts the conditional quantum-noise suppression into the unconditional one without significant loss of the noise

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Ryotaro Inoue, Shin-Ichi-Ro Tanaka, Ryo Namiki, Takahiro Sagawa, Yoshiro Takahashi. 2013-01-06. Unconditional quantum-noise suppression via measurement-based quantum feedback. https://doi.org/10.1103/physrevlett.110.163602

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