Squeezing with a flux-driven Josephson parametric amplifier
ORAL
Abstract
Josephson parametric amplifiers (JPA) are promising devices for the implementation of continuous-variable quantum communication protocols. Operated in the phase-sensitive mode, they allow for amplifying a single quadrature of the electromagnetic field without adding any noise. While in practice internal losses introduce a finite amount of noise, our device still adds less noise than an ideal phase-insensitive amplifier. This property is a prerequisite for the generation of squeezed states. In this work, we reconstruct the Wigner function of squeezed vacuum, squeezed thermal and squeezed coherent states with our dual-path method [L. Zhong et al. arXiv:1307.7285 (2013); E. P. Menzel et al. Phys. Rev. Lett. 105 100401 (2010)]. In addition, we illuminate the physics of squeezed coherent microwave fields. This work is supported by SFB 631, German Excellence Initiative via NIM, EU projects SOLID, CCQED, PROMISCE and SCALEQIT, MEXT Kakenhi ``Quantum Cybernetics,'' JSPS FIRST Program, the NICT Commissioned Research, Basque Government IT472-10, Spanish MINECO FIS2012-36673-C03-02, and UPV/EHU UFI 11/55.
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