Feshbach resonances, weakly bound molecular states and coupled-channel potentials for cesium at high magnetic fields

TL;DR

This paper investigates ultracold cesium atom scattering at high magnetic fields, identifying new Feshbach resonances, measuring molecular binding energies, and developing a refined interaction potential model for precise control of scattering properties.

Contribution

It introduces a new 6-parameter long-range interaction potential model, M2012, based on experimental data, improving the accuracy of scattering length predictions for cesium.

Findings

Identified 17 new Feshbach resonances in cesium at high magnetic fields.

Measured binding energies of cesium dimer states using magnetic field modulation spectroscopy.

Developed the M2012 potential model that accurately maps scattering length to magnetic field.

Abstract

We explore the scattering properties of ultracold ground-state Cs atoms at magnetic fields between 450 G (45 mT) and 1000 G. We identify 17 new Feshbach resonances, including two very broad ones near 549 G and 787 G. We measure the binding energies of several different dimer states by magnetic field modulation spectroscopy. We use least-squares fitting to these experimental results, together with previous measurements at lower field, to determine a new 6-parameter model of the long-range interaction potential, designated M2012. Coupled-channels calculations using M2012 provide an accurate mapping between the s-wave scattering length and the magnetic field over the entire range of fields considered. This mapping is crucial for experiments that rely on precise tuning of the scattering length, such as those on Efimov physics.