The Cooper pair from radio-frequency excitations in ultracold gases
  We discuss the concept of Cooper pair in the context of recent experimental studies of radio-frequency excitations in ultracold atomic gases. We argue that the threshold energy determines the size of the Cooper pair emergent from the exact solution of the reduced BCS problem, and elaborate on the physical distinction between bosonic and fermionic Cooper pairs. 
J. Dukelsky and G. Ortiz