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An effective theory of Feshbach resonances and many-body properties of Fermi gases

G. M. Bruun·C. J. Pethick
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Abstract

For calculating low-energy properties of a dilute gas of atoms interacting via a Feshbach resonance, we develop an effective theory in which the parameters that enter are an atom-molecule coupling strength and the magnetic moment of the molecular resonance. We demonstrate that for resonances in the fermionic systems $^{6}$Li and $^{40}$K that are under experimental investigation, the coupling is so strong that many-body effects are appreciable even when the resonance lies at an energy large compared with the Fermi energy. We calculate a number of many-body effects, including the effective mass and the lifetime of atomic quasiparticles in the gas.

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G. M. Bruun, C. J. Pethick. 2004-04-17. An effective theory of Feshbach resonances and many-body properties of Fermi gases. https://doi.org/10.1103/physrevlett.92.140404

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