Shrinking of a condensed fermionic cloud in a trap approaching the BEC limit

Abstract

We determine the zero-temperature density profile of a cloud of fermionic atoms in a trap subject to a mutual attractive interaction, as the strength of the interaction is progressively increased. We find a significant decrease of the size of the atomic cloud as it evolves from the weak-coupling (BCS) regime of overlapping Cooper pairs to the strong-coupling (Bose-Einstein) regime of non-overlapping bound-fermion pairs. Most significantly, we find a pronounced increase of the value of the density at the center of the trap (even by an order of magnitude) when evolving between the two regimes. Our results are based on a generalized Thomas-Fermi approximation for the superfluid state, that covers continuously all coupling regimes.

5 pages, 3 postscript figures

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• Fermi-Bose quantum degenerate ^40 K - ^87 Rb mixture with attractive interaction
• Influence of Induced Interactions on the Superfluid Transition in Dilute Fermi Gases
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