Modeling flux tunability in Josephson Traveling Wave Parametric Amplifiers with an open-source frequency-domain simulator

TL;DR

This paper demonstrates the use of an open-source frequency-domain simulator, JosephsonCircuits.jl, to efficiently model flux tunability in Josephson Traveling Wave Parametric Amplifiers, achieving significant speedups over traditional time-domain methods.

Contribution

The work introduces a frequency-domain simulation approach for flux-tunable JTWPAs, validated against experimental data, and offers a much faster alternative to existing time-domain tools.

Findings

Frequency-domain simulation is about 10,000 times faster than time-domain methods.

The numerical results closely match experimental data.

The approach effectively models flux-dependent behavior of JTWPAs.

Abstract

Josephson Traveling Wave Parametric Amplifiers (JTWPAs) are integral parts of many experiments carried out in quantum technologies. Being composed of hundreds of Josephson junction-based unit cells, such devices exhibit complex nonlinear behavior that typically cannot be fully explained with simple analytical models, thus necessitating the use of numerical simulators. A very useful characteristic of JTWPAs is the possibility of being biased by an external magnetic flux, allowing insitu control of the nonlinearity. It is therefore very desirable for numerical simulators to support this feature. Open-source numerical tools that allow to model JTWPA flux biasing, such as WRSPICE or PSCAN2, are based on time-domain approaches,which typically require long simulation times to get accurate results. In this work, we model the gain performance in a prototypical flux-tunable JTWPA by using JosephsonCircuits.jl,a recently developed frequency-domain open-source numerical simulator, which has the benefit of simulation times about 10,000 faster than time-domain methods. By comparing the numerical and experimental results, we validate this approach for modeling the flux dependent behavior of JTWPAs.