Berlin 2024 – scientific programme
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QI: Fachverband Quanteninformation
QI 18: Poster II
QI 18.12: Poster
Wednesday, March 20, 2024, 11:00–14:30, Poster A
Faithful extraction of internal quality factors in overcoupled tunable superconducting resonators — •Kedar E. Honasoge1,2, Yuki Nojiri1,2, Maria-Teresa Handschuh1,2, Daniil E. Bazulin1,2, Leon Koch1,2, Thomas Luschmann1,2, Niklas Bruckmoser1,2, Florian Fesquet1,2, Achim Marx1, Rudolf Gross1,2,3, and Kirill G. Fedorov1,2,3 — 1Walther-Meißner-Institut, 85748 Garching, Germany — 2School of Natural Sciences, Technische Universität München, 85748 Garching, Germany — 3Munich Center for Quantum Science and Technology (MCQST), 80799 München, Germany
In quantum information processing, advancing superconducting circuits to reach ever-higher coherence times and internal quality factors has been a key focus. However, the faithful extraction of internal quality factors from reflection measurements of overcoupled resonators represents a long-standing problem due to its large intrinsic, Fano-type, uncertainty in the fitting procedures. Here, we develop a particular solution for this problem by considering a typical tunable superconducting resonator weakly coupled to an antenna circuit, which allows for additional transmission measurements. We develop an input-output model for this case and apply it to our experimental data by simultaneously fitting both the reflection and transmission data. We demonstrate that this approach significantly increases accuracy of the extracted internal quality factors. Finally, we discuss extensions of our method to other types of superconducting quantum circuits.
Keywords: Superconducting Circuits; Internal quality factors; Josephson Parametric Amplifiers