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A: Fachverband Atomphysik
A 33: Precision Spectroscopy of Atoms and Ions V (joint session A/Q)
A 33.1: Vortrag
Freitag, 10. März 2023, 14:30–14:45, B302
Superconducting magnetic shielding for trapped ion qubits — •Elwin A. Dijck1, Christian Warnecke1,2, Claudia Volk1, Stepan Kokh1, Kostas Georgiou1,3, Lakshmi P. Kozhiparambil Sajith1,4,5, Christopher Mayo1,3, Andrea Graf1, José R. Crespo López-Urrutia1, and Thomas Pfeifer1 — 1Max Planck Institute for Nuclear Physics, Heidelberg — 2Heidelberg University — 3University of Birmingham, United Kingdom — 4DESY, Zeuthen — 5Humboldt University of Berlin
Merging a linear Paul trap with a superconducting RF resonator produces a trapping environment with minimal magnetic field noise, ideal for precision spectroscopy and (highly charged) ion qubits. We characterize our ion trap of this type built from niobium [1] using microwave spectroscopy of Be+ hyperfine qubits, determining the magnetic field stability and shielding factor. Due to flux trapping, the magnetic field applied during cooldown remains present in the ion trap and no external field needs to be applied during subsequent trap operation at cryogenic temperature. We find the trapped magnetic field to be stable over a period of months with relative changes at the 10−10 s−1 level. Additionally, magnetic field noise, which often limits qubit coherence, is passively shielded by the superconductor at all frequencies down to DC. Using Ramsey interferometry and spin echo measurements, we find coherence times of >100 ms without active field stabilization.
[1] J. Stark et al., Rev. Sci. Instrum. 92, 083203 (2021)