Cooper pairing in ultracold 40K using Feshbach resonances -: art. no. 053409

We point out that the fermionic isotope K-40 is a likely candidate for the formation of Cooper pairs in an ultracold atomic gas. Specifically, in an optical trap that simultaneously traps the spin states \9/2,- 9/2] and \9/2,-7/2], there exists a broad magnetic-field Feshbach resonance at B = 196(-21)(+9) G that can provide the required strong attractive interaction between atoms. An additional resonance, at B = 191(10)(+5) G, could generate p-wave pairing between identical \9/2,-7/2] atoms. A Cooper-paired degenerate Fermi gas could thus be constructed with existing ultracold-atom technology.