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Achieving a BCS transition in an atomic Fermi gas
We consider a gas of cold fermionic atoms having two spin components with
interactions characterized by their s-wave scattering length . At positive
scattering length the atoms form weakly bound bosonic molecules which can be
evaporatively cooled to undergo Bose-Einstein condensation, whereas at negative
scattering length BCS pairing can take place. It is shown that, by
adiabatically tuning the scattering length from positive to negative
values, one may transform the molecular Bose-Einstein condensate into a highly
degenerate atomic Fermi gas, with the ratio of temperature to Fermi temperature
. The corresponding critical final value of
which leads to the BCS transition is found to be about one half, where is
the Fermi momentum.Comment: 4 pages, 1 figure. Phys. Rev. Lett. in pres
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