Observation of Feshbach-like resonances in collisions between ultracold molecules

TL;DR

This paper reports the observation of Feshbach-like resonances in ultracold Cs2 molecule collisions, demonstrating tunable interactions that could enable controlled chemical reactions and synthesis of complex molecules.

Contribution

First observation of magnetically tuned Feshbach-like resonances in ultracold molecules, revealing new pathways for controlling molecular interactions.

Findings

Identification of Feshbach-like resonances as inelastic loss features

Magnetic levitation used to measure molecular magnetic moments

Resonances attributed to Cs4 bound states near scattering continuum

Abstract

We observe magnetically tuned collision resonances for ultracold Cs2 molecules stored in a CO2-laser trap. By magnetically levitating the molecules against gravity, we precisely measure their magnetic moment. We find an avoided level crossing which allows us to transfer the molecules into another state. In the new state, two Feshbach-like collision resonances show up as strong inelastic loss features. We interpret these resonances as being induced by Cs4 bound states near the molecular scattering continuum. The tunability of the interactions between molecules opens up novel applications such as controlled chemical reactions and synthesis of ultracold complex molecules.