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arXiv · 2303.10940

Ab initio calculation of the spectrum of Feshbach resonances in NaLi + Na collisions

Tijs Karman·Marcin Gronowski·Michal Tomza·Juliana J. Park·Hyungmok Son·Yu-Kun Lu·Alan O. Jamison·Wolfgang Ketterle
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Abstract

We present a combined experimental and theoretical study of the spectrum of magnetically tunable Feshbach resonances in NaLi $(a^3Σ^+)$ $+$ Na collisions. In the accompanying paper, we observe experimentally 8 and 17 resonances occur between $B=0$ and $1400$~G in upper and lower spin-stretched states, respectively. Here, we perform ab initio calculations of the NaLi $+$ Na interaction potential and describe in detail the coupled-channel scattering calculations of the Feshbach resonance spectrum. The positions of the resonances cannot be predicted with realistic uncertainty in the state-of-the-art ab initio potential, but our calculations yield a typical number of resonances that is in near-quantitative agreement with experiment. We show that the main coupling mechanism results from spin-rotation and spin-spin couplings in combination with the anisotropic atom-molecule interaction. The calculations furthermore explain the qualitative difference between the numbers of resonances in either spin state.

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Tijs Karman, Marcin Gronowski, Michal Tomza, Juliana J. Park, Hyungmok Son, Yu-Kun Lu, Alan O. Jamison, Wolfgang Ketterle. 2023-07-10. Ab initio calculation of the spectrum of Feshbach resonances in NaLi + Na collisions. https://doi.org/10.1103/physreva.108.023309

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