Quantum 2025 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
MON: Monday Contributed Sessions
MON 14: QIP Implementations: Solid-State Devices I
MON 14.2: Talk
Monday, September 8, 2025, 16:45–17:00, ZHG002
Sub-harmonic control of a fluxonium qubit via a Purcell-protected flux line — •Christian Schneider1,2, Johannes Schirk1,2, Florian Wallner1,2, Longxiang Huang1,2, Ivan Tsitsilin1,2, Niklas Bruckmoser1,2, Leon Koch1,2, Klaus Liegener1,2, and Stefan Filipp1,2,3 — 1Walther-Meißner-Insitut, Bayerische Akademie der Wissenschaften, 85748 Garching — 2Technische Universität München, TUM School of Natural Sciences, 85748 Garching — 3Munich Center for Quantum Science and Technology (MCQST), 80799 München
Isolating qubits from environmental noise while maintaining fast, high-fidelity control is a central challenge in quantum information processing. In this talk, I present our findings on isolating a superconducting fluxonium qubit from its noisy control environment while maintaining fast, high-fidelity control. We achieve this by adding a low-pass filter below the qubit frequency, which suppresses resonant coupling between the qubit and the control channel. Although this prevents resonant qubit control, we overcome the limitation by driving the qubit at integer fractions of its transition frequency, allowing us to achieve Rabi oscillations through the Purcell-protected channel. We demonstrate coherent control using up to 11-photon processes through driving the qubit at 1/11 of its resonant frequency and have developed an effective Hamiltonian model using a Magnus expansion, which accurately predicts the observed behavior. These results open a scalable approach for fluxonium control via a single Purcell-protected channel, preserving intrinsic qubit coherence while allowing for fast, high-fidelity control.
Keywords: superconducting; qubits; fluxonium; control; purcell