Freiburg 2024 – scientific programme
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A: Fachverband Atomphysik
A 35: Poster VIII
A 35.11: Poster
Thursday, March 14, 2024, 17:00–19:00, Tent C
Dynamics of melting linear mixed-species Coulomb crystals — •Elwin A. Dijck1, Luca A. Rüffert2, Lars Timm3, José R. Crespo López-Urrutia1, and Tanja E. Mehlstäubler2,3 — 1Max Planck Institute for Nuclear Physics, Heidelberg — 2Physikalisch-Technische Bundesanstalt, Braunschweig — 3Leibniz University, Hannover
We investigate the disappearance of ordered structure with increasing system temperature of linear ion Coulomb crystals trapped in a linear radiofrequency trap using molecular dynamics simulations. Understanding these dynamics is valuable for optimizing the operation of multi-ion optical clocks and experiments using highly charged ions for tests of fundamental physics. The thermal motion at higher temperature causes ions to swap places at increasing rates, depending on ion properties and trapping parameters. In particular, we study how the melting dynamics are affected by the presence of ion species with differing charge and/or mass. We support the simulation results with experimental data of small Be+ ion crystals with and without a highly charged ion, controlling the ion temperature using Doppler cooling/heating. We discuss different criteria for defining the melting point and how the increased Coulomb repulsion by a highly charged ion alters the crystal structure such that these mixed-species ion crystals exhibit localized melting.
Keywords: Ion Coulomb crystals; Thermodynamics; Molecular dynamics simulation; Highly charged ions