Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 49: Poster Session: Superconductivity
TT 49.43: Poster
Wednesday, April 3, 2019, 15:00–18:30, Poster D
Time resolved quantum sensing of microwave frequencies and fields with transmons — •Maximilian Kristen1, Andre Schneider1, Alexander Stehli1, Tim Wolz1, Alexey V. Ustinov1,2, and Martin Weides1,3 — 1Karlsruhe Institute of Technology, Karlsruhe, Germany — 2Russian Quantum Center, National University of Science and Technology MISIS, Moscow, Russia — 3University of Glasgow, Glasgow, UK
Within the last years, quantum sensing has become a steadily growing field of research leading to numerous new technologies. For instance, it was recently demonstrated that off-resonant anharmonic quantum systems, e.g., transmon qubits, work as sensors for extremely weak microwave signals which are usually not measurable with conventional room-temperature electronics due to thermal background noise. However, these spectroscopic proof of principle experiments offered limited precision for reasonable data acquisition times [1]. In this work, we explore the opportunities provided by time resolved measurements. Using Ramsey fringes, we determine the shift of the first and second qubit transition induced by the applied microwave signal. This allows us to infer amplitude and frequency of this signal with a precision of a few MHz. From numerical simulations of the system we find that perturbative treatment of the transmon Hamiltonian yields insufficient results for the sensing scheme at this level of precision. Finally, we discuss the implementation of a phase estimation algorithm, enabling us to further increase the sensitivity and speed of our sensor.
A.Schneider et al., Phys. Rev. A 97, 062334 (2018)