Speaker
Description
When s-wave scattering length diverges in the vicinity of Feshbach resonances the system of three particles exhibits bound states characterized by universal properties [1,2]. A well-known fact is that near a narrow Feshbach resonance the existence range of these states shrinks down as a function of the narrowness of the resonance. Empirically, however, this is not the case for bosonic lithium. An unexpected behavior is observed experimentally when the three-body bound state is shown to resist dissociation into atom-dimer continuum at the threshold [3]. Simplified theoretical analysis pointed out that asymptotic behavior of the three-body potential fails to explain this peculiarity [4,5]. Only a more involved theory which includes the van-der Waals tail of the two-body interaction potential shows unusual reshaping of the three-body interactions due to repulsive interactions in the atom-dimer channel [6]. We thus identify the reason for quasi-stationary property of the three-body bound state embedded into atom-dimer continuum.
In addition, I will describe our effort toward the study of lithium BEC at different scattering length zero crossings. A new experimental apparatus is being built for this purpose where we demonstrate a novel design of Zeeman slower based on standard permanent magnets.
[1] C. H. Greene, P. Giannakeas, J. Péres-Ríos, Rev. Mod. Phys. 89, 035006 (2017).
[2] P. Naidon, S. Endo, Rep. Prog. Phys. 80, 056001 (2017).
[3] Y. Yudkin, R. Elbaz, L. Khaykovich, arXiv:2004.02723
[4] Y. Yudkin, L. Khaykovich, Phys. Rev. A 103, 063303 (2021).
[5] Y. Yudkin, P. S. Julienne, L. Khaykovich, Phys. Rev. A, accepted for publication (2023).
[6] Y. Yudkin, R. Elbaz, J. P. D’Incao, P. S. Julienne and L. Khaykovich, in preparation.
