Observation of 4.2-K equilibrium-noise squeezing via a Josephson-parametric amplifier

B. Yurke; P. G. Kaminsky; R. E. Miller; E. A. Whittaker; A. D. Smith; A. H. Silver; R. W. Simon

doi:10.1103/PhysRevLett.60.764

Observation of 4.2-K equilibrium-noise squeezing via a Josephson-parametric amplifier

B. Yurke, P. G. Kaminsky, R. E. Miller, E. A. Whittaker, A. D. Smith, A. H. Silver, and R. W. Simon

Phys. Rev. Lett. 60, 764 – Published 29 February 1988

Abstract

We have demonstrated 42% squeezing of 4.2-K thermal noise using a Josephson-parametric amplifier operated at 19.4 GHz. The amplifier has been operated at 0.1 K with an excess noise of 0.28 K referred to the input port. This is less than the vacuum fluctuation noise hν/2k=0.47 K at 19.4 GHz. The amplifier thus is less noise than a linear phase-insensitive amplifier such as a maser could in principle be.