Projects per year
Abstract
We revisit the properties of the twocomponent Fermi gas with shortrange interactions in three dimensions, in the limit where the swave scattering length diverges. Such a unitary Fermi gas possesses universal thermodynamic and dynamical observables that are independent of any interaction length scale. Focusing on trapped systems of N fermions, where N ≤ 10, we investigate how well we can determine the zerotemperature behavior of the manybody system from published fewbody data on the groundstate energy and the contact. For the unpolarized case, we find that the Bertsch parameters extracted from trapped fewbody systems all lie within 15% of the established value. Furthermore, the fewbody values for the contact are well within the range of values determined in the literature for the manybody system. In the limit of large spin polarization, we obtain a similar accuracy for the polaron energy, and we estimate the polaron's effective mass from the dependence of its energy on N. We also compute an upper bound for the squared wavefunction overlap between the unitary Fermi system and the noninteracting ground state, both for the trapped and uniform cases. This allows us to prove that the trapped unpolarized ground state at unitarity has zero overlap with its noninteracting counterpart in the manybody limit N → ∞.
Original language  English 

Article number  072001 
Number of pages  11 
Journal  Journal of Physics B: Atomic, Molecular and Optical Physics 
Volume  50 
Issue number  7 
DOIs  
Publication status  Published  16 Mar 2017 
Keywords
 degenerate Fermi gas
 fewbody physics
 strongly correlated systems
 ultracold atomic gases
Projects
 1 Finished

Density modulations and superconductivity in twodimensional quantum gases
Parish, M., Levinsen, J. & Bruun, G.
Australian Research Council (ARC), Monash University, Aarhus Universitet (Aarhus University)
1/01/16 → 31/12/19
Project: Research