Precise determination of $^6$Li cold collision parameters by radio-frequency spectroscopy on weakly bound molecules

TL;DR

This study uses radio-frequency spectroscopy on weakly bound $^6$Li molecules to accurately measure molecular energies and extract ultracold atomic interaction parameters, refining the understanding of Feshbach resonances.

Contribution

It provides precise measurements of $^6$Li molecular binding energies and interaction parameters using radio-frequency spectroscopy, enhancing ultracold collision models.

Findings

Determined singlet and triplet scattering lengths with high precision.

Identified the positions of three broad Feshbach resonances.

Improved parameters for ultracold $^6$Li collision models.

Abstract

We employ radio-frequency spectroscopy on weakly bound $^6$Li$_2$ molecules to precisely determine the molecular binding energies and the energy splittings between molecular states for different magnetic fields. These measurements allow us to extract the interaction parameters of ultracold $^6$Li atoms based on a multi-channel quantum scattering model. We determine the singlet and triplet scattering lengths to be $a_s=45.167(8)a_0$ and $a_t=-2140(18)a_0$ (1 $a_0$ = 0.0529177 nm), and the positions of the broad Feshbach resonances in the energetically lowest three $s-$wave scattering channels to be 83.41(15) mT, 69.04(5) mT, and 81.12(10) mT.