Improving the efficiency of ultracold dipolar molecule formation by first loading onto an optical lattice

TL;DR

This paper proposes a method to nearly double the efficiency of ultracold dipolar molecule formation by loading atoms into an optical lattice, reducing losses and increasing molecule density at higher temperatures.

Contribution

The authors introduce a scheme that enhances molecule formation efficiency to nearly 100% by using an optical lattice to control atomic occupancy and interactions.

Findings

Efficiency increased to nearly 100%

Reduces three-body recombination loss

Effective at relatively high temperatures

Abstract

Ultracold ground state dipolar 40K-87Rb molecules have recently been produced in a loose harmonic trap by employing a magnetic field sweep across a Feshbach resonance followed by stimulated Raman adiabatic passage [K.-K. Ni et al., Science 322, 231 (2008)]. The overall experimental efficiency for molecule formation was around 20%. We show that the efficiency can be increased to nearly 100% if one first loads the atomic gases into an optical lattice of the appropriate depth and tunes the interspecies attraction to have exactly one atom of each species at an occupied lattice site. Our proposed scheme provides a large enhancement to the dipolar molecule density even at relatively high temperatures, and avoids three-body recombination loss by preventing lattice sites from being triply occupied.