Ultracold atom-ion collisions: Landau quantization and scattering resonances

Dariusz Wiater, Michał Tomza

Bo Gao, A. Dalgarno

Andrea Simoni, Jean–Michel Launay

We study ultracold atom–ion collisions in the presence of an external magnetic field. At low collision energy the field can drastically modify the translational motion of the ion, which follows quantized cyclotron orbits. We present a rigorous theoretical approach for the calculation of quantum scattering amplitudes in these conditions. Collisions in different magnetic field regimes, identified by the size of the cyclotron radius with respect to the range of the interaction potential, are investigated. Our results are important in cases where use of a magnetic field to control the atom–ion collision dynamics is envisioned.

Marko Gacesa, Robin Côté

We investigate ultracold collisions of heteroisotopic pairs of Ca with Ca + mediated by an external magnetic field. Based on the nuclear spin of Ca, namely I = 7/2 for 43 Ca and I = 0 for other isotopes, we identify different scattering dynamics and characterize magnetic Feshbach resonances in 43 Ca+ 43 Ca + and 43 Ca+ (40,42) Ca + collisions. Our results suggest that interisotopic Feshbach resonances could be used to control charge-exchange in ultracold atom-ion mixtures of Ca and its ion.

Diego C. B. Valente, Robin C ot 'e

Meirav Pinkas, Jonathan M. Wengrowicz, Nitzan Akerman +1 more

Abstract we report on signatures of classical chaos in ultracold collisions between a trapped ion and a free atom. Using numerical simulations, we show that the scattering dynamics can be highly sensitive to initial conditions for various mass ratios and trapping frequencies, indicating the onset of chaos. We quantify this chaotic dynamics by calculating its fractal dimension. We show that for a trapped 88 Sr + ion and a free 87 Rb atom chaotic dynamic appears under experimentally relevant conditions, and find its characteristic energy scale. The observation of classical chaos in atom-trapped-ion collisions suggests that signatures of quantum chaos might appear, for example, through a Wigner–Dyson distribution of collisional resonances.