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THU: Thursday Contributed Sessions
THU 13: Poster Session: Applications
THU 13.1: Poster
Thursday, September 11, 2025, 16:30–18:30, ZHG Foyer 1. OG
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
Superconducting qubits are currently limited by decoherence, making the identification of loss mechanisms critical for improving system performance. We investigate dissipation in Josephson junction arrays, a key component of protected qubits such as fluxonium and zero-pi qubits. To probe these loss channels, we study high-impedance lumped-element LC resonators composed of two charge islands connected by a Josephson junction array. This architecture closely resembles that of fluxonium qubits but enables more direct characterization through transmission measurements. We focus on power dependence spectroscopy and time traces of the resonator transmission. With this we achieve a fast and efficient characterization of the junction parameters and quality, providing a robust method to improve Josephson junction performance for fluxoniums and protected circuits.
Keywords: quantum computing; qubit; fluxonium; junction array; resonator