Electromagnetic Modeling and Scripted Quantum Parameter Extraction of 3D Superconducting Qubits Using PathWave EMPro

We present the analysis of 3D superconducting qubits using PathWave EMPro with its scripting feature that enables quantum parameter extraction and design automation of 3D qubits. In the electromagnetic study, the qubits are represented by their ‘linearized’ lumped inductances at very low signal excitation, and then for a full description of the quantum system, the nonlinear quantum parameters are extracted. We consider here the configuration in Ref. [1] as a showcase example of a 3D qubit with published measurements. Qubit anharmonicities and cross-Kerr strengths are calculated from both the frequency domain response using black-box quantization [2] and from the eigenmode solution using the energy participation method [3], [4]. For a rigorous nonlinear analysis, the frequency response of the 3D qubit using a nonlinear Josephson junction model is produced in PathWave ADS Co-simulation environment. Both the linear and nonlinear analyses in PathWave tools yield similar circuit responses, which validate the accuracy of EMPro to simulate 3D superconducting qubits.