Berlin 2024 – scientific programme

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QI: Fachverband Quanteninformation

QI 18: Poster II

QI 18.4: Poster

Wednesday, March 20, 2024, 11:00–14:30, Poster A

Transmon qubit as an absolute power sensor at milli-Kelvin temperatures — •Asen Lyubenov Georgiev, Fabian Kaap, Thomas Weimann, Alexander Fernández Scarioni, Victor Gaydamachenko, Christoph Kissling, Bhoomika Ravi Bhat, Mark Bieler, and Lukas Grünhaupt — Physikalisch-Technische Bundesanstalt

Superconducting quantum bits (qubits) are the basic elements of quantum computational devices. When operating qubits at milli-Kelvin temperatures with a series of cryogenic components on the electrical lines the exact attenuation is not known. Therefore, the resulting microwave power in the cryogenic environment is not predictable a priori. However, qubits can be used as very sensitive power sensors in the 3 to 8 GHz range, and we can measure the microwave power without the need for further dedicated devices. Here, we present a transmon-based circuit, a specific realization of superconducting qubit, which allows us to harness their power sensing capabilities. Finally, we measure and evaluate the absolute power sensing capabilities of the fabricated devices.

Keywords: Transmon; Superconducting qubits; Power sensor; AC Stark shift; Simulation