Precise, detailed error budgets for 2-qubit gates from gate set tomography*

Gate set tomography (GST) is widely known as a procedure for finding process matrices that describe quantum gates.  We recently introduced a new representation of noisy gates using error generators (arXiv:2103.01928), and integrated it with GST.  In this representation, GST's output is a simple, comprehensive, high-precision error budget for each gate.  It also enables GST to characterize and report streamlined error models that focus exclusively on a particular system's dominant errors.  We discuss several recent high-profile experiments (especially arXiv:2106.03082) that use this capability to report precise, detailed error budgets for 2-qubit gates.