Formation of bosonic $^{23}$Na$^{41}$K Feshbach molecules

TL;DR

This paper demonstrates the creation of bosonic $^{23}$Na$^{41}$K Feshbach molecules via RF association at a broad interspecies resonance, providing a foundation for ultracold dipolar molecule research.

Contribution

It reports the first creation and characterization of $^{23}$Na$^{41}$K Feshbach molecules, including resonance properties and molecule lifetime measurements.

Findings

Up to 11,000 molecules created from thermal mixture.

Resonance width measured at 5.1 G, enabling control.

Molecule lifetime exceeds 2 ms, up to 7 ms after removing Na.

Abstract

Ultracold Feshbach molecules are a crucial intermediate step for the creation of quantum degenerate gases of strongly dipolar molecules. After coherent transfer to the rovibrational ground state, these dimers can realize stable dipolar gases with strong, tunable long-range interactions. Here, we report the creation of bosonic $^{23}$Na$^{41}$K Feshbach molecules by radio-frequency (RF) association. An RF pulse applied on the molecular side of an interspecies Feshbach resonance at 73.6(1)~G associates up to $1.1(1)\times10^4$ molecules from a thermal mixture of $^{23}$Na and $^{41}$K atoms. Measurements of the binding energy reveal a broad resonance width of 5.1(2)~G, facilitating robust control over interspecies interactions. The molecule lifetime in the presence of background atoms exceeds 2~ms, extending to 7~ms after removal of $^{23}$Na. These results constitute a key step toward the production of ultracold $^{23}$Na$^{41}$K ground state molecules for the exploration of novel many-body phenomena in strongly dipolar Bose gases.