Regensburg 2025 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 11: Superconductivity: Poster
TT 11.42: Poster
Monday, March 17, 2025, 15:00–18:00, P4
Understanding loss channels in fluxonium qubits through high-impedance LC resonators — •Matthias Zetzl1,2,3, Johannes Schirk1,2,3, Florian Wallner1,2,3, Ivan Tsitsilin1,2,3, Niklas Bruckmoser1,2,3, Christian Schneider1,2,3, and Stefan Filipp1,2,3 — 1Walther-Meißner-Institut, Garching, Germany — 2Technische Universität München, Munich, Germany — 3Munich Center for Quantum Science and Technology, Munich, Germany
Current quantum systems based on superconducting qubits are limited by their rate of information loss. Therefore, identifying and mitigating the sources of decoherence of individual qubits is key to improve the performance of these systems. Here, we investigate loss mechanisms in Josephson junction arrays, which are commonly used to implement protected qubits such as "fluxonium" or "zero-pi" qubits. To probe these loss channels, we characterize high-impedance lumped-element LC resonators, comprised of two charge islands connected by a Josephson junction array. While this architecture closely resembles that of "fluxonium" qubits, it allows for a more straightforward characterization by direct transmission measurements of the resonators. By extracting the internal quality factor of the resonators, we can assess the fabrication quality of the junctions in a fast and efficient way, providing a useful tool for all junction based components.
Keywords: quantum computing; qubit; fluxonium; junction array; resonator