Quantum mixtures of atoms and ions: road to ultracold

Ultracold atoms and trapped ions are among the most formidable sources of coherent matter available in a laboratory. In a hybrid quantum system of atoms and ions, ultracold atoms and trapped ions are combined in a single experimental apparatus, thus realizing an innovative platform to experimentally investigate open problems of quantum physics from a new standpoint. An atom-ion hybrid system not only brings together the advantages of each single physical system, but moreover gives rise to atom-ion interactions, which can be used as a new tool in the “quantum toolbox”.

In the talk, I will review some of the most recent results in atom-ion physics, including the use of atom-ion collisions for sympathetically cool the ions, and the applications in molecular physics. I will report on the strategy we are pursuing to reach a coherent control of atom-ion interactions. In particular, I will show a new trap that we have conceived for confining ions only with static electric and optical fields. This electro-optical trap is embedded with a Paul trap, which was designed in order to maximize the trap matching between the two confining potentials.
The specific geometry of these traps [1] make it possible to continuously change the arrangement of the ions from a one-dimensional string to a two-dimensional crystal, and to study specific phenomena in two-dimensional crystals of ions, such as the occurrence of orientational melting [2], and the formation of metastable, “isomeric” states of the crystal.

[1] E. Perego, et al. Appl. Sci. 10, 2222 (2020)
[2] L. Duca, et. al. Phys. Rev. Lett. 131, 083602 (2023)