2016/09/28 by Stefan Pogorzalek, Kirill G. Fedorov, Ling Zhong +11 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.supr-con #quant-ph
paper · pdf · doi:10.1103/physrevapplied.8.024012
published as Phys. Rev. Applied 8, 024012 (2017) · 9 pages, 6 figures
arxiv created 2016/09/28 · arxiv updated 2017/08/22
Josephson parametric amplifiers (JPA) have become key devices in quantum science and technology with superconducting circuits. In particular, they can be utilized as quantum-limited amplifiers or as a source of squeezed microwave fields. Here, we report on the detailed measurements of five flux-driven JPAs, three of them exhibiting a hysteretic dependence of the resonant frequency versus the applied magnetic flux. We model the measured characteristics by numerical simulations based on the two-dimensional potential landscape of the dc superconducting quantum interference devices (dc-SQUID), which provide the JPA nonlinearity, for a finite screening parameter βL > 0 and demonstrate excellent agreement between the numerical results and the experimental data. Furthermore, we study the nondegenerate response of different JPAs and accurately describe the experimental results with our theory.