High-Fidelity Entangling Gates with Tunable Couplers: Part 2

Two-qubit entangling gate error is the most important metric for development of robust systems of interacting qubits. Approaches involving tunable couplers are needed to suppress idle errors to an acceptable level. Here we describe an optimized circuit involving tunable transmons that interact via a tunable coupler. In this second part of a two-part presentation, we describe circuit fabrication and bringup and characterization of both iSWAP and CZ gate error.