Fast, Scalable Calibration of a Quantum Annealer

Quantum annealers require a variety of calibration procedures, including calibration of crosstalk between flux bias lines, characterization of coupler strengths and qubit Ising parameters as a function of control flux, and optimization of readout.  Flux crosstalk in particular can be data intensive as the number of individual measurements scales as O(N²) with the number of control biases.

We provide details on methods developed to increase the velocity of data acquisition such that data for an individual calibrated value can be collected and analyzed in a few seconds. Characterization methods are described for calibrating as-fabbed circuit parameters for each individual circuit element to increase control precision. These are considered in the context of calibration and control of a 25-qubit quantum annealer with individual control, having over 200 flux control lines.

This material is based upon work supported by the Defense Advanced Research Projects Agency under Air Force Contract No. FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Defense Advanced Research Projects Agency.