Buffer gas cooling and trapping of atoms with small magnetic moments

TL;DR

This paper extends buffer gas cooling techniques to trap atoms with small magnetic moments, demonstrating effective cooling and trapping for moments down to 1.1 mu_B, and analyzing loss processes affecting efficiency.

Contribution

It introduces methods to cool and trap atoms with small magnetic moments using buffer gas, expanding the range of atoms accessible for ultracold experiments.

Findings

Successfully cooled and trapped atoms with mu ≥ 3mu_B.

Limited trapping efficiency for mu < 3mu_B due to wind and helium films.

Extrapolation suggests potential to trap mu = 1mu_B atoms.

Abstract

Buffer gas cooling was extended to trap atoms with small magnetic moment (mu). For mu greater than or equal to 3mu_B, 1e12 atoms were buffer gas cooled, trapped, and thermally isolated in ultra high vacuum with roughly unit efficiency. For mu < 3mu_B, the fraction of atoms remaining after full thermal isolation was limited by two processes: wind from the rapid removal of the buffer gas and desorbing helium films. In our current apparatus we trap atoms with mu greater than or equal to 1.1mu_B, and thermally isolate atoms with mu greater than or equal to 2mu_B. Extrapolation of our results combined with simulations of the loss processes indicate that it is possible to trap and evaporatively cool mu = 1mu_B atoms using buffer gas cooling.