Ionization rates in a Bose-Einstein condensate of metastable Helium

TL;DR

This study investigates ionization processes in a Bose-Einstein condensate of metastable Helium, quantifying two- and three-body collision contributions and their impact on atom loss, highlighting quantum depletion effects.

Contribution

It provides the first detailed measurement of ionization rates in a He* BEC, including quantum depletion corrections to the 3-body rate constant.

Findings

Ionization largely causes atom loss in the BEC.

Quantum depletion significantly affects the 3-body rate constant.

Measured ionization rates enable estimation of collision contributions.

Abstract

We have studied ionizing collisions in a BEC of He*. Measurements of the ion production rate combined with measurements of the density and number of atoms for the same sample allow us to estimate both the 2 and 3-body contributions to this rate. A comparison with the decay of the number of condensed atoms in our magnetic trap, in the presence of an rf-shield, indicates that ionizing collisions are largely or wholly responsible for the loss. Quantum depletion makes a substantial correction to the 3-body rate constant.