Trapped ions in an ultracold gas: buffer gas cooling and chemical reactions*

Hybrid ion-atom systems combine the benefits of a single, well-controlled ion with those of a many-body quantum gas, offering prospects for quantum simulation, ultracold chemistry, and charged impurity physics. In this talk I will present recent experiments, where we observed collisions between Li₂ dimers and a single Yb+ ion, leading to the formation of a LiYb+ molecular ion [1]. Our results show a new method for molecular ion formation and for probing an atom cloud for small quantities of dimers. Furthermore, I will present numerical simulations for cooling our system further into the quantum regime [2]. Ion trap parameter optimization will allow buffer gas cooling to energies competitive with some sub-Doppler laser cooling techniques, reaching atom-ion collision energies twice as cold as previous experiments [3].

[1] H. Hirzler et al. arXiv:2110.14475 (2021)

[2] E. Trimby et al. arXiv:2109.15195 (2021)

[3] T. Feldker et al. Nat. Phys. 4, 16 (2020)