Mainz 2026 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 27: Poster – Precision Spectroscopy of Atoms and Ions (joint session A/Q)
Q 27.22: Poster
Tuesday, March 3, 2026, 17:00–19:00, Philo 1. OG
Ground-state cooling of mixed-ion crystals in the intermediate Lamb-Dicke regime — •Sebastian Davidson, Elwin A. Dijck, Vera M. Schäfer, Ruben Henninger, Devanarayanan Rajeeb Kumar, Shreya K. Rao, José R. Crespo López-Urrutia, and Thomas Pfeifer — Max-Planck-Institut für Kernphysik, Heidelberg
Ground-state cooling of motional modes in mixed-species ion crystals is a key requirement for implementing quantum logic spectroscopy of highly charged ions (HCIs). Building on our demonstrated ground-state cooling of both single Be+ ions and two-ion Be+ crystals using a combination of continuous sideband cooling on higher-order sidebands and pulsed sideband cooling, we extend these techniques to a Be+-Ar13+ two-ion crystal. Since our current trap operates in an intermediate Lamb-Dicke regime with η up to 0.7 for the mixed species crystal, we explore adapted cooling strategies that remain effective outside the Lamb-Dicke limit. We report our progress toward achieving ground-state cooling of axial modes of a Be+-Ar13+ crystal under these conditions, including characterization and optimization of cooling sequences. These advances represent an essential step toward full quantum logic spectroscopy of HCIs and the high-precision tests of fundamental physics that they enable.
Keywords: Quantum Logic Spectroscopy; Ion Traps; Highly Charged Ions; Optical Clocks; Sideband Cooling