We have shown that two-channel Feshbach theory works well to describe p-wave Feshbach resonances , however a peculiar result of a non-intuitive molecular magnetic moment led to the realization that an additional shape resonance was part of the scattering problem and unaccounted for.
We study how two shape resonances in separate hyperfine channels in Potassium-40 interact with a Feshbach resonance. To account for all resonances, we need (at least) a three-channel model. This is theoretically and computationally highly involved.
However, as full coupled-channels calculations reveal a strong magnetic field dependence of the atom loss between the two hyperfine channels that contain the shape resonances, we approximate the coupling between the shape resonances to be purely facilitated by the Feshbach channel.
This greatly simplifies the three-channel model and allows us to retrieve the standard Breitt-Wigner form of the scattering matrix with corrected values of the resonance width and resonance shift resulting from the presence of the third channel. We reveal that, contrary to the resonant two-channel model used in our previous analysis , the resonance-facilitated three-channel model can consistently match full coupled channels calculations with physically realistic input parameters.
Hence, it captures physics beyond the reach of the standard two-channel Feshbach approach.
 D. J. M. Ahmed-Braun, K. G. Jackson, S. Smale, C. J. Dale, B. A. Olsen, S. J. J. M. F. Kokkelmans, P. S. Julienne, J. H. Thywissen, Probing open- and closed-channel p-wave resonances, Phys. Rev. Research 3, 033269 (2021).
|Presenter name||Denise Ahmed-Braun|
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