Toward an automatic parallelized two-qubit-gate calibration

Abstract

Calibrating a large quantum processor is a challenging task as it requires optimizing many parameters for each gate. As the number of gates increases, the amount of human intervention must be reduced to a minimum and an automatic calibration must be developed to carry out all these complex calibrations. The quantum processor developed by the quantum computing group at Chalmers is already complex enough to require such automation, as it contains 25 qubits. The group has developed an application, called Tergite automatic calibration, that can perform single-qubit calibration but is not yet capable of calibrating two-qubit gates. This Master’s thesis focuses on this crucial missing functionality; in this work, a fully automatic calibration procedure is presented that can calibrate two-qubit gates for the 25-qubit chip. Two key aspects have been considered in this work; the possibility of reliably finding operational points that can be used for the calibrations of the desired two-qubit gate and the possibility do this for multiple couplers in parallel. Robustness measurements are presented to show that the autocalibration procedure can reliably find the calibration parameters in different conditions. Crucially, the algorithm developed is not only capable of calibrating multiple two-qubit gates, but it can do so in a relatively fast enough time to allow reliable operations on the quantum processor.