WMI Seminar: Control of Quantum Devices: Merging Pulse Calibration and System Characterization using Optimal Control

May 18

When:     Friday, May 18, 2018, 13:30 h
Location: Bayerische Akademie der Wissenschaften, Walther-Meißner-Institut, Seminar Room 143(or Room 128 if noisy)

Dr. Shai Machnes, Universität des Saarlandes, will give a seminar on "Control of Quantum Devices: Merging Pulse Calibration and System Characterization using Optimal Control".


The current methodology for designing control pulses for quantum devices circuits often results
in a somewhat absurd situation: pulses are designed using simplified models, resulting in initially
poor fidelities. The pulses are then calibrated in-situ, achieving high-fidelities, but without a
corresponding model. We are therefore left with a model we know is inaccurate, working pulses
for which we do not have a matching model, and a calibration process from which we learned
nothing about the system. We propose a novel procedure to rectify the situation, by merging
pulse design, calibration and system characterization: Calibration is recast as a closed-loop search
for the best-fit model parameters, starting with a detailed, but only partially characterized model
of the system. Fit is evaluated by fidelity of a complete set of gates, which are optimized to fit the
current system characterization. The end result is a best-fit characterization of the system model,
and a full set of high-fidelity gates for that model. We believe the new approach will greatly
improve both gate fidelities and our understanding of the systems they drive.
Shai Machnes, Elie Assémat, David Tannor, and Frank K. Wilhelm. Tunable, Flexible, and Efficient
Optimization of Control Pulses for Practical Qubits. Phys. Rev. Lett. 120, 150401 (2018).

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