Observation of 4.2 equilibrium noise squeezing via a Josephson-parametric amplifier
Bernard Yurke, P. G. Kaminsky, Ronald Earle Miller, Edward A. Whittaker, A. D. Smith, Arnold H. Silver, R. W. Simon · IEEE Transactions on Magnetics · 1989
The authors observed the squeezing of 4.2 K thermal noise using a Josephson parametric amplifier operated in the degenerate mode at 19.4 GHz. A 42% reduction in the equilibrium noise was observed. The amplifier has also been operated at 0.1 K with an excess noise of 0.28 K referred to the amplifier's input port. This is less than the vacuum fluctuation noise of 0.47 K at the amplifier's input. Recently the amplifier has been operated in a nonchaotic mode with a signal gain in excess of 16 dB.>