Spectroscopy and Ground-State Transfer of Ultracold Bosonic $^{39}$K$^{133}$Cs Molecules

TL;DR

This paper demonstrates the creation and spectroscopy of ultracold $^{39}$K$^{133}$Cs molecules in their ground state, achieving high efficiency and providing insights into loss mechanisms, advancing quantum matter research.

Contribution

The study identifies a new pathway to produce ultracold ground-state molecules using narrow intermediate states and STIRAP, with high efficiency and insights into loss processes.

Findings

Created ultracold $^{39}$K$^{133}$Cs molecules in ground state

Achieved 71% transfer efficiency with STIRAP

Observed near-universal two-body loss limiting lifetime

Abstract

We report the creation of ultracold samples of $^{39}$K$^{133}$Cs molecules in their rovibrational ground state. By investigating potentially suitable excited states using one- and two-photon spectroscopy, we have identified a pathway to the ground state via an exceptionally narrow intermediate state. Using Stimulated Raman Adiabatic Passage (STIRAP), we create trapped samples of up to 3500 molecules at temperatures of 1 $\mu$K with one-way efficiencies of 71%. The lifetime of these samples is limited by a near-universal two-body loss process, which could shed new light on similar loss mechanisms in other molecular species. Our results are a step towards establishing an alternative platform for the study of bosonic and fermionic quantum matter with strong dipolar interactions.