Optimal Operation of a Josephson Parametric Amplifier for Vacuum Squeezing
M. Malnou, D. A. Palken, Leila R. Vale, Gene C. Hilton, K. W. Lehnert · Physical Review Applied · 2018
``Squeezed'' states of the microwave field, which allow one to beat the Heisenberg uncertainty limit for some phase values, find diverse applications in improving quantum measurements. These states can be created using a Josephson parametric amplifier (JPA) operated with a single current pump, but nonlinearities limit the available squeezing. The authors show how to choose pump-tone parameters to reduce this distortion, so that anyone with such a JPA can squeeze harder for better measurements, without needing extra hardware or a more complicated scheme.