Optimization of two-qubit gate rates and crosstalk in a tunable coupling superconducting device

The implementation of fast and high-fidelity quantum gates involves a multitude of parameters governing important properties of the system, such as the gate rate, leakage and the extent of spurious interactions. One therefore needs to carefully choose these parameters to optimize the gate fidelity and speed. We study the case of two far detuned fixed frequency transmons coupled through a flux-tunable coupler. Here, we present the results of a parameter search run to maximize gate rates while minimizing unwanted cross-Kerr interaction using a method based on Floquet theory. We also estimate variations on the quantities of interest due to imprecision in device fabrication. Finally, we study spectator effects in a multi-qubit chip.

This work was undertaken thanks in part to funding from NSERC, the Canada First Research Excellence Fund, the Ministère de l'Économie et de l'Innovation du Québec, and the ARO grant No. W911NF-18-1-0411.