Atom-ion Feshbach resonances controlled by quantum statistics

Researchers at Albert-Ludwigs-Universität Freiburg and collaborating institutions have demonstrated a pronounced nonlinear dependence between ion loss rate and spin polarization in a unique hybrid system. The work centers on a single trapped ion immersed in a two-component Fermi gas of lithium atoms near an atom-ion Feshbach resonance, allowing isolation of quantum statistics in atom-atom-ion collisions. The observations reveal that antisymmetrization restricts available pathways during recombination, leading to interference between indistinguishable processes. This establishes atom-ion systems as a platform for controlling three-body collisions via quantum statistics. This arrangement allows precise control over the spin composition of the lithium gas, a key parameter in isolating the influence of quantum statistics on collision dynamics. Calculated density profiles for both fully polarized and mixed lithium atom clouds reveal a significant difference in central density, with the mixed cloud exhibiting a higher concentration for a total atom count of 40,000, though this difference remains unresolved by current experimental resolution. Establishing a spin-independent density calibration was a necessary step before investigating the polarization dependence of atom-atom-ion interactions, performed s-wave Feshbach resonance at a…