Evaporative cooling of cold atoms at surfaces

TL;DR

This paper combines theoretical modeling and experimental validation to study evaporative cooling of cold rubidium atoms near surfaces, highlighting the importance of collisional dynamics for optimizing condensate purity and size.

Contribution

It introduces a coupled dissipative Gross-Pitaevskii and quantum Boltzmann model for surface cooling, validated by experiments, to optimize condensate production.

Findings

Model accurately captures key physics with full collisional dynamics

Experimental data agrees with theoretical predictions

Guidelines for optimizing surface cooling for larger condensates

Abstract

We theoretically investigate the evaporative cooling of cold rubidium atoms that are brought close to a solid surface. The dynamics of the atom cloud are described by coupling a dissipative Gross-Pitaevskii equation for the condensate with a quantum Boltzmann description of the thermal cloud (the Zaremba-Nikuni-Griffin method). We have also performed experiments to allow for a detailed comparison with this model and find that it can capture the key physics of this system provided the full collisional dynamics of the thermal cloud are included. In addition, we suggest how to optimize surface cooling to obtain the purest and largest condensates.