BCS-BEC crossover with a finite-range interaction
  We study the crossover from BEC to BCS pairing for dilute systems but with a realistic finite-range interaction. We exhibit the changes in the excitation spectrum that provide a clean qualitative distinction between the two limits. We also study how the dilute system converges to the results from a zero-range pseudo-potential derived by Leggett. 
Meera M. Parish, Bogdan Mihaila, Eddy M. Timmermans, Krastan B.   Blagoev, and Peter B. Littlewood