Full control of Josephson nonlinear processes in a Gradiometric SNAIL Parametric Amplifier*

Superconducting parametric amplifiers rely on nonlinear processes in order to coherently amplify readout photons with the addition of a minimal amount of noise limited just by Quantum Mechanics principles. A precise tuning of these processes is required to achieve 20dB gain at the readout tone frequency and, simultaneously, obtain a Kerr-free operation in order to reduce undesired effects as gain compression. State-of-the-art parametric amplifiers are capable of Kerr-free operation at a single frequency only, depending on the design parameters of the device. In this work, we present experimental results on the Gradiometric SNAIL Parametric Amplifier (GSPA), a device biased by two independent on-chip magnetic fluxes that allow to independently tune even and odd Josephson nonlinearities. Such a device is capable of 20dB Kerr-free amplification over a continuous range of frequency, providing a shortcut towards the development of a precision and universal parametric amplifier for optimal readout of many-qubit platforms.