Purdue University Graduate School
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posted on 2022-11-09, 13:11 authored by Yu-Hsin ChenYu-Hsin Chen


P-wave Efimov physics for three equal mass fermions with different symmetries has been modeled using two-body interactions of Lennard-Jones potentials between each pair of Fermi atoms, and is predicted to modify the long range three-body interaction potential energies, but without producing a real Efimov effect. Our analysis treats the following trimer angular momenta and parities, LΠ = 0+,1+,1 and 2, for either three spin-up fermions (↑↑↑), or two spin-up and one spin-down fermion (↑↓↑). Our results for the long range behavior in some of those cases agree with previous work by Werner and Castin and by Blume et al., namely in cases where the s-wave scattering length goes to infinity. This thesis extends those calculated interaction energies to small and intermediate hyperradii comparable to the van der Waals length, and considers additional unitarity scenarios where the p-wave scattering volume approaches infinity. The crucial role of the diagonal hyperradial adiabatic correction term is identified and characterized. For the equal mass fermionic trimers with two different spin components near the unitary limit are shown to possess a universal van der Waals bound or resonance state near s-wave unitarity, when p-wave interactions are included between the particles with equal spin. Our treatment uses a single-channel Lennard-Jones interaction with long range two-body van der Waals potentials. While it is well-known that there is no true Efimov effect that would produce an infinite number of bound states in the unitary limit for these fermionic systems, we demonstrate that another type of universality emerges for the symmetry LΠ = 1. The universality is a remnant of Efimov physics that exists in this system at p-wave unitarity, and it leads to modified threshold and scaling laws in that limit. Application of our model to the system of three lithium atoms studied experimentally by Du, Zhang, and Thomas [Phys. Rev. Lett. 102, 250402 (2009)] yields a detailed interpretation of their measured three-body recombination loss rates. 


NSF Grant No. PHY1912350


Degree Type

  • Doctor of Philosophy


  • Physics and Astronomy

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Chris H. Greene

Additional Committee Member 2

Francis Robicheaux

Additional Committee Member 3

Chen-Lung Hung

Additional Committee Member 4

Sabre Kais