Automatic Calibration and Characterization of Quantum Devices - Experimental Results on NISQ QPUs and Quantum Memory devices

The practical application of optimal control techniques, especially in superconducting settings, requires extensive calibration to reach high fidelities. By controlling both experiment and a high performance numerical simulation, the C3 procedure provides a framework to systematically design and apply even intricate open loop optimal control pulses.

We demonstrate the characterization and tune-up of a quantum computing device with a few qubit, as well as a quantum memory device composed of a transmon with a 3D microwave cavity. The memory experiment presents different challenges, as the control protocol involves high-power sideband transitions, leading to system dynamics that are incompatible with simple models for qubit-cavity interactions.

In both cases, we numerically simulate the measurement of gate sequences and, by comparing the results to experimental data, improve the model of the experiment, including both simple parameters such as qubit frequencies, as well as non-trivial aspects such as line responses and bandwidth limitations of the electronic equipment that distort and imposes constraints on control signals.