Feshbach resonances and weakly bound molecular states of boson-boson and boson-fermion NaK pairs

TL;DR

This paper provides a theoretical analysis of Feshbach resonances and bound states in NaK isotopic pairs, accurately matching experimental data and predicting properties for less-studied isotopes to facilitate molecule formation.

Contribution

The study introduces a comprehensive model that reproduces experimental Feshbach spectra and predicts resonance features for multiple NaK isotopes, aiding ultracold molecule research.

Findings

Reproduces experimental Feshbach resonance data for Na$^{40}$K

Predicts broad Feshbach resonances in Na$^{39}$K and Na$^{41}$K

Identifies favorable conditions for molecule formation in Na$^{39}$K

Abstract

We study theoretically magnetically induced Feshbach resonances and near-threshold bound states in isotopic NaK pairs. Our calculations accurately reproduce Feshbach spectroscopy data on Na$^{40}$K and explain the origin of the observed multiplets in the p-wave [Phys. Rev. A 85, 051602(R) (2012)]. We apply the model to predict scattering and bound state threshold properties of the boson-boson Na$^{39}$K and Na$^{41}$K systems. We find that the Na$^{39}$K isotopic pair presents broad magnetic Feshbach resonances and favorable ground-state features for producing non-reactive polar molecules by two-photon association. Broad s-wave resonances are also predicted for Na$^{41}$K collisions.