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Amplitude and frequency sensing of microwave fields with a superconducting transmon qudit



Maximilian Kristen, Andre Schneider, Alexander Stehli, Tim Wolz, Sergey Danilin, Hsiang S. Ku, Junling Long, Xian Wu, Russell Lake, David P. Pappas, Alexey V. Ustinov, Martin Weides


Experiments with superconducting circuits require careful calibration of the applied pulses and fields over a large frequency range. This remains an ongoing challenge as commercial semiconductor electronics are not able to probe signals arriving at the chip due to its cryogenic environment. Here, we demonstrate how the on-chip amplitude and frequency of a microwave signal can be inferred from the ac Stark shifts of higher transmon levels. In our time-resolved measurements we employ Ramsey fringes, allowing us to detect the amplitude of the systems transfer function over a range of several hundreds of MHz with an energy sensitivity on the order of 10-4. Combined with similar measurements for the phase of the transfer function, our sensing method can facilitate pulse correction for high fidelity quantum gates in superconducting circuits. Additionally, the potential to characterize arbitrary microwave fields promotes applications in related areas of research, such as quantum optics or hybrid microwave systems including photonic, mechanical or magnonic subsystems.
Physics Arxiv


superconducting circuits, calibration, applied pulses, commercial semiconductor electronics, cryogenic environment, on-chip amplitude, ac Stark shifts, higher transmon levels, Ramsey fringes, pulse correction, quantum gates, microwave fields, quantum optics, photonic, mechanical, magnonic, subsystems


Kristen, M. , Schneider, A. , Stehli, A. , Wolz, T. , Danilin, S. , Ku, H. , Long, J. , Wu, X. , Lake, R. , Pappas, D. , Ustinov, A. and Weides, M. (2020), Amplitude and frequency sensing of microwave fields with a superconducting transmon qudit, Physics Arxiv, [online],, (Accessed July 15, 2024)


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Created May 20, 2020, Updated October 12, 2021