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Formation of bosonic Na23K41 Feshbach molecules

Sungjun Lee*, Younghoon Lim*,†, Jongyeol Kim, Jaeryeong Chang, and Jee Woo Park‡

  • *These authors contributed equally to this work.
  • †Present address: 3rd R&D Institute, Agency for Defense Development, Daejeon 34186, Republic of Korea.
  • ‡Contact author: jeewoopark@postech.ac.kr
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Phys. Rev. Research 8, 023307 – Published 17 June, 2026

DOI: https://doi.org/10.1103/s4bx-31b6

Abstract

Ultracold Feshbach molecules are a crucial intermediate step for the creation of quantum degenerate gases of strongly dipolar molecules. After coherent transfer to the rovibrational ground state, these dimers can realize stable dipolar gases with strong, tunable long-range interactions. Here, we report the creation of bosonic Na23K41 Feshbach molecules by radio-frequency (RF) association. An RF pulse applied on the molecular side of an interspecies Feshbach resonance at 73.6(1) G associates up to 1.1(1)×104 molecules from a thermal mixture of Na23 and K41 atoms. Measurements of the binding energy reveal a broad resonance width of 5.1(2) G, facilitating robust control over interspecies interactions. The molecule lifetime in the presence of background atoms exceeds 2 ms and increases to approximately 7 ms after removal of Na23. These results constitute a key step toward the production of ultracold Na23K41 ground-state molecules and for pursuing shielded evaporative cooling in the dipolar regime.

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Outline

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Phys. Rev. Research 8, 023307– Published 17 June, 2026
  • Received 6 February 2026
  • Accepted 3 May 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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