A process which strongly amplifies both quadrature amplitudes of an oscillatory signal necessarily adds noise. Alternatively, if the information in one quadrature is lost in phase-sensitive amplification, it is possible to completely reconstruct the other quadrature. Here we demonstrate such a nearly perfect phase-sensitive measurement using a cavity optomechanical scheme, characterized by an extremely small noise less than 0.2 quanta. We also observe microwave radiation strongly squeezed by 8 dB below vacuum. A source of bright squeezed microwaves opens up applications in manipulations of quantum systems, and noiseless amplification can be used even at modest cryogenic temperatures.
@article{arxiv.1610.09980,
title = {Noiseless quantum measurement and squeezing of microwave fields utilizing mechanical vibrations},
author = {C. F. Ockeloen-Korppi and E. Damskägg and J. -M. Pirkkalainen and T. T. Heikkilä and F. Massel and M. A. Sillanpää},
journal= {arXiv preprint arXiv:1610.09980},
year = {2017}
}