Condensed Matter Seminar: Fermions meet two bosons: From the heteronuclear Efimov effect to heavy Fermi polarons

Binh Tran (Heidelberg university)
In this talk I will first revisit the heteronuclear Efimov effect considering two heavy bosons and one light fermion, allowing us to work in the Born-Oppenheimer approximation.

November 09, 2020

Binh Tran (Heidelberg university)
Online Seminar
Mon 9. November 2020, 11:30 am (MEZ)

Abstract:

In this talk I will first revisit the heteronuclear Efimov effect considering two heavy bosons and one light fermion, allowing us to work in the Born-Oppenheimer approximation. Two limiting cases of the Efimov scenario are presented, first, in vacuum, and second, in the presence of a Fermi Sea.
The first case reproduces well-known features of the Efimov effect, in particular the infinite series of three-body bound states. The intraspecies scattering length determines the three-body parameter and the scaling factor between consecutive Efimov states.
For the second case, I will present how the Fermi Sea leads to the suppression of bound states and a modified Efimov scaling law incorporating the Fermi momentum. At energies above the continuum threshold, we find that the Efimov state may turn into a quasi-bound state with a finite decay width. Moreover, the scattering phase shifts and scattering lengths between the two heavy impurities are computed, giving insight into effective interactions between Fermi polarons.
Lastly, I will discuss experimental protocols to study polaron physics in a 6Li-133Cs experiment.

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