Evaporative cooling and ultracold collisions of silver atoms: Towards a Bose-Einstein condensate of Ag
POSTER
Abstract
Ultracold francium-silver (FrAg) molecules are promising candidates for use in a search for CP-violating physics beyond the Standard Model [1,3,4]. Efficiently assembling such molecules from Fr and Ag atoms demands atomic samples with ultracold temperatures, high phase-space density, and magnetically-controllable collisions. Realizing a silver Bose-Einstein condensate (BEC)—a milestone yet to be achieved—is an important benchmark for this control.
In this poster, we present our progress towards the first BEC of silver. We use a dark SPOT MOT to trap ~1x109 atoms [5] and apply Λ-enhanced gray molasses to cool them to ~15 μK. This enables the loading of ~1x106 atoms into a crossed optical dipole trap, for either of the two isotopes (107Ag and 109Ag, each with nuclear spin I=½). We report on the observation of inelastic losses, collisional resonances,and evaporative cooling. Furthermore, we discuss efforts aimed at determining the zero-field scattering lengths [6] and other collisional properties. These combined efforts are starting to pave the way for realizing a degenerate gas of Ag atoms and establishing the essential toolbox for full quantum control of ultracold silver, as needed for the assembly of ultracold FrAg molecules.
[1] J. Kłos et al., New J. Phys. 24, 025005 (2022).
[2] M. Śmiałkowski and M. Tomza, Phys. Rev. A 103, 022802 (2021).
[3] T. Fleig and D. DeMille, New J. Phys. 23, 113039 (2021).
[4] V. Spevak et al., Phys. Rev. C 56, 1357 (1997).
[5] M. Vayninger et al., Phys. Rev. A 112, 063306 (2025).
[6] E. Tiesinga et al., Phys. Rev. A 111, 062814 (2025).
In this poster, we present our progress towards the first BEC of silver. We use a dark SPOT MOT to trap ~1x109 atoms [5] and apply Λ-enhanced gray molasses to cool them to ~15 μK. This enables the loading of ~1x106 atoms into a crossed optical dipole trap, for either of the two isotopes (107Ag and 109Ag, each with nuclear spin I=½). We report on the observation of inelastic losses, collisional resonances,and evaporative cooling. Furthermore, we discuss efforts aimed at determining the zero-field scattering lengths [6] and other collisional properties. These combined efforts are starting to pave the way for realizing a degenerate gas of Ag atoms and establishing the essential toolbox for full quantum control of ultracold silver, as needed for the assembly of ultracold FrAg molecules.
[1] J. Kłos et al., New J. Phys. 24, 025005 (2022).
[2] M. Śmiałkowski and M. Tomza, Phys. Rev. A 103, 022802 (2021).
[3] T. Fleig and D. DeMille, New J. Phys. 23, 113039 (2021).
[4] V. Spevak et al., Phys. Rev. C 56, 1357 (1997).
[5] M. Vayninger et al., Phys. Rev. A 112, 063306 (2025).
[6] E. Tiesinga et al., Phys. Rev. A 111, 062814 (2025).
*We thank the National Science Foundation and the Gordon and Betty Moore Foundation for support of this project.
Publication: Vayninger, M., Xiang, A., Bhanushali, N. D., Chen, X., Verma, M., Yang, S., Kapur, R. T., DeMille, D., & Yan, Z. Z. (2025). Magneto-optical trap of silver and potassium atoms. Physical Review A, 112(6), 063306.
Presenters
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Shaozhen Yang
- University of Chicago