Bogoliubov theory of Feshbach molecules in the BEC-BCS crossover

Abstract

We present the Bogoliubov theory for the Bose-Einstein condensation of Feshbach molecules in a balanced Fermi mixture. Because the Bogoliubov theory includes (Gaussian) fluctuations, we can in this manner accurately incorporate both the two-body and many-body aspects of the BEC-BCS crossover that occurs near a Feshbach resonance. We apply the theory in particular to the very broad Feshbach resonance in atomic Li-6 at a magnetic field of B_0 = 834 G and find good agreement with experiments in that case. The BEC-BCS crossover for more narrow Feshbach resonances is also discussed.

13 pages of RevTex and 12 Figures. Submitted for publication in Physical review A

References in corpus (7)

• Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Molecular Probe of Pairing in the BEC-BCS Crossover
• Pure Gas of Optically Trapped Molecules Created from Fermionic Atoms
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• Theory of ultracold Fermi gases
• Imbalanced Fermi Gases at Unitarity
• Renormalisation Flow and Universality for Ultracold Fermionic Atoms
• BCS-BEC crossover in dense relativistic matter: Collective excitations
• Anomalous Behavior of Dark States in Quantum Gases of 6Li
• Renormalized mean-field theory for a two-component Fermi gas with s-wave interactions
• Interacting Preformed Cooper Pairs in Resonant Fermi Gases
• Periodic dynamics of fermionic superfluids in the BCS regime
• Post-adiabatic Hamiltonian for low-energy excitations in a slowly time-dependent BCS-BEC crossover