2021/10/06 by Brian J. McMahon, Brian C. Sawyer
Chemistry · Physics and Astronomy · #Advanced Frequency and Time Standards #Algorithm #Analytical Chemistry (journal) #Atomic and Molecular Physics #Atomic physics #Chemistry #Cold Atom Physics and Bose-Einstein Condensates #Computer science #Hyperfine structure #Magnetic field #Physics #Quantum mechanics #physics.atom-ph #quant-ph
paper · pdf · doi:10.1103/physrevapplied.17.014005
published as Phys. Rev. Applied 17, 014005 (2022) · 6 pages, 4 figures
arxiv created 2021/10/06 · openalex publication_date 2022/01/05 · arxiv updated 2022/01/11 · openalex created_date 2022/01/25 · openalex updated_date 2026/06/30
We report microwave spectroscopy of co-trapped 9Be+ and 40Ca+ ions within a compact permanent-magnet-based Penning ion trap. The trap is constructed with a reconfigurable array of Nd-Fe-B rings providing a 0.654-T magnetic field that is near the 0.6774-T magnetic-field-insensitive hyperfine transition in 9Be+. Performing Ramsey spectroscopy on this hyperfine transition, we demonstrate nuclear spin coherence with a contrast decay time of >1 s. The 9Be+ is sympathetically cooled by a Coulomb crystal of 40Ca+, which minimizes 9Be+ illumination and thus mitigates reactive loss. Introducing a unique high-magnetic-field optical-detection scheme for 40Ca+, we perform spin-state readout without a 729-nm shelving laser. We record a fractional trap magnetic field instability below 20 ppb (13 nT) at 43 s of averaging time with no magnetic shielding and only passive thermal isolation. We discuss potential applications of this compact reconfigurable Penning trap.