Population of closed-channel molecules in trapped Fermi gases with broad Feshbach resonances

Abstract

We compute the fraction of closed-channel molecules in trapped atomic Fermi gases, over the entire range of accessible fields and temperatures. We use a two-channel model of BCS--Bose-Einstein condensation (BEC) crossover theory at general temperature $T$, and show that this fraction provides a measure of the $T$ dependent pairing gap. Our calculations, containing no free parameters, are in good quantitative agreement with recent low $T$ measurements in ${}^6$Li. We present readily testable predictions for the dependencies of the closed-channel fraction on temperature and Fermi momentum.

4 pages, 3 figures, published in PRL

References in corpus (3)

• Molecular Probe of Pairing in the BEC-BCS Crossover
• Dressed Feshbach molecules in the BEC-BCS crossover
• Simple Mean-Field Theory for a Zero-Temperature Fermi Gas at a Feshbach Resonance

Cited by in corpus (17)

• Universal Properties of the Ultra-Cold Fermi Gas
• Renormalisation Flow and Universality for Ultracold Fermionic Atoms
• Pseudogap phenomena in ultracold atomic Fermi gases
• Phase diagram of a polarized Fermi gas across a Feshbach resonance in a potential trap
• Dressed Feshbach molecules in the BEC-BCS crossover
• BCS-BEC crossover and quantum phase transition for 6Li and 40K atoms across Feshbach resonance
• Role of Particle Interactions in the Feshbach Conversion of Fermion Atoms to Bosonic Molecules
• Pair fraction in a finite temperature Fermi gas on the BEC side of the BCS-BEC crossover
• Bogoliubov theory of Feshbach molecules in the BEC-BCS crossover
• Dressed-molecules in resonantly-interacting ultracold atomic Fermi gases
• Observation of the density dependence of the closed-channel fraction of a ${}^6$Li superfluid
• Superfluidity and pairing phenomena in ultracold atomic Fermi gases in one-dimensional optical lattices, Part I: Balanced case
• Fermionic superfluidity: From high Tc superconductors to ultracold Fermi gases
• Superfluidity in atomic Fermi gases
• Closed-channel parameters of Feshbach resonances
• Mean-field stationary state of a Bose gas at a Feshbach resonance
• Fast mode of rotating atoms in one-dimensional lattice rings