The interaction-sensitive states of a trapped two-component ideal Fermi gas and application to the virial expansion of the unitary Fermi gas

Shimpei Endo, Yvan Castin

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4 Citations (Scopus)


We consider a two-component ideal Fermi gas in an isotropic harmonic potential. Some eigenstates have a wavefunction that vanishes when two distinguishable fermions are at the same location, and would be unaffected by s-wave contact interactions between the two components. We determine the other, interaction-sensitive eigenstates, using a Faddeev ansatz. This problem is nontrivial, due to degeneracies and to the existence of unphysical Faddeev solutions. As an application we present a new conjecture for the fourth-order cluster or virial coefficient of the unitary Fermi gas, in good agreement with the numerical results of Blume and coworkers.
Original languageEnglish
Article number265301
Pages (from-to)1-28
Number of pages28
JournalJournal of Physics A: Mathematical and Theoretical
Issue number26
Publication statusPublished - 24 May 2016
Externally publishedYes


  • cluster expansion
  • Fermi gases
  • quantum few-body problem
  • ultracold atoms
  • unitary Fermi gas
  • virial expansion

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