Unconditional quantum-noise suppression via measurement-based quantum feedback

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 $-0.80_{-0.12}^{+0.11}\mathrm{dB}$ 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

10 pages, 8 figures, 1 table

References in corpus (4)

• Quantum teleportation between light and matter
• Experimental demonstration of quantum memory for light
• Second Law of Thermodynamics with Discrete Quantum Feedback Control
• Spin squeezing of a cold atomic ensemble with the nuclear spin of one-half