IQIM Virtual Seminar, December 4, 2020 - Xin Xie

Speaker: Xin Xie, IQIM Postdoctoral Scholar, Endres Group
Title: Precise Calibrations of Few-Body Physics in Potassium-39
Abstract: We perform precise studies of two-and three-body interactions near an intermediate-strength Feshbach resonance in potassium-39 at 33.5820(14) G. Precise measurement of dimer binding energies enables the construction of a complete two-body coupled-channel model for determination of the scattering lengths with an unprecedented low uncertainty. Utilizing such an accurate scattering length map, we unambiguously locate four distinct features in the Efimov three-body structure. Meticulous characterization of and correction for finite temperature effects ensure high accuracy on the measurements of these features at large-magnitude scattering lengths. We report the ground Efimov resonance location to be at −14.05(17) times the van der Waals length r_vdW, significantly deviating from the value of −9.7r_vdW predicted by van der Waals universality [1]. While three of these features form ratios that obey the Efimov universal scaling to within 10% [2].
[1] journals.aps.o...
[2] journals.aps.o...