Observation of zero-point noise squeezing via a Josephson-parametric amplifier

Abstract
We have demonstrated (47±8)% squeezing of vacuum-fluctuation noise using a Josephson-parametric amplifier operated at 19.16 GHz. The amplifier was operated at 30 mK and has a double-sideband noise temperature of 0.446 K. This is comparable to the vacuum noise floor hν/2k=0.460 K.