Control, Calibration and Characterization of a simulated two-transmon chip. Part 2*

On the road towards high-fidelity quantum computers, it is desirable to obtain a model of the physical system that is detailed enough to understand the limits of gate fidelity. Such a process is arduous and impractical with increasing chip size.
Using optimal control, we show a systematic way to evaluate and analyze a model prediction of experimental data and use it to construct a matching goal function. As an application example, we present the characterization of a two-qubit QPU in simulation. Our goal function expresses the likelihood that the noisy calibration data is predicted by a candidate model. We then optimize the parameters of the candidate, like qubit frequency and couplings, to improve the match and enrich the model to include open-system effects, control line distortions and SPAM errors.

[1] Wittler, N., et.al. An integrated tool-set for Control, Calibration and Characterization arXiv:2009.09866