Observation of Cold Collisions between Trapped Ions and Trapped Atoms

TL;DR

This study demonstrates a system for observing cold collisions between trapped ions and atoms, measuring collision rates at very low energies, and comparing results with theoretical models.

Contribution

It introduces a double-trap setup for studying cold ion-atom collisions and provides experimental data consistent with semiclassical Langevin theory.

Findings

Collision rate coefficient measured at $6 imes 10^{-10}$ cm$^{3}$s$^{-1}$

Rate coefficient remains constant over four orders of magnitude in energy

Results agree with semiclassical Langevin model

Abstract

We demonstrate a double-trap system well suited to study cold collisions between trapped ions and trapped atoms. Using Yb$^+$ ions confined in a Paul trap and Yb atoms in a magneto-optical trap, we investigate charge-exchange collisions of several isotopes for collision energies down to 400 neV (5 mK). The measured rate coefficient of $6 \times 10^{-10}$ cm$^{3}$s$^{-1}$, constant over four orders of magnitude in collision energy, is in good agreement with that derived from a semiclassical Langevin model for an atomic polarizability of 143 a.u.