Baseband and Microwave Crosstalk in Superconducting Qubits

High-fidelity gate operations in superconducting quantum processors are often limited by classical crosstalk from control lines. Here, we describe the characterization of baseband and microwave crosstalk in qubit chips incorporating either microfabricated airbridge crossovers or dense wirebond stitching. We discuss simple physical models for scaling of this crosstalk and implications for large-scale processor design.