Improving Quantum Gate Fidelities by Using a Qubit to Measure Microwave Pulse Distortions

We present a new method for determining pulse imperfections and improving the single-gate fidelity in a superconducting qubit. By applying consecutive positive and negative π pulses, we amplify the qubit evolution due to microwave pulse distortions, which causes the qubit state to rotate around an a...

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Bibliographic Details
Main Authors: Gustavsson, Simon, Zwier, Olger, Bylander, Jonas, Yan, Fei, Yoshihara, Fumiki, Nakamura, Yasunobu, Orlando, Terry Philip, Oliver, William D.
Other Authors: Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Format: Article
Language:en_US
Published: American Physical Society 2013
Online Access:http://hdl.handle.net/1721.1/78360
https://orcid.org/0000-0002-7069-1025
https://orcid.org/0000-0002-4674-2806
https://orcid.org/0000-0002-4436-6886
Description
Summary:We present a new method for determining pulse imperfections and improving the single-gate fidelity in a superconducting qubit. By applying consecutive positive and negative π pulses, we amplify the qubit evolution due to microwave pulse distortions, which causes the qubit state to rotate around an axis perpendicular to the intended rotation axis. Measuring these rotations as a function of pulse period allows us to reconstruct the shape of the microwave pulse arriving at the sample. Using the extracted response to predistort the input signal, we are able to reduce the average error per gate by 37%, which enables us to reach an average single-qubit gate fidelity higher than 0.998.